Systems and methods for manufacturing cast steel alloy crankshafts with low porosity

Abstract

This invention relates to a system and method for manufacturing cast steel alloy crankshafts with low porosity. A system and method for manufacturing cast steel alloy crankshafts for internal combustion engines are provided. The method includes providing a mold for the crankshaft. The mold has a cavity to form the crankshaft. The method further includes melting a first metallic material between 1400 degrees Celsius (°C) and 1600 degrees Celsius to define the molten metallic material. Furthermore, the method further includes feeding the molten metallic material into the cavity of a sand casting mold at a riser connection angle between 30° and 75°. The method further includes cooling the molten metallic material in a sand casting mold having at least one cooling member for a solidification time between 5 seconds and 20 seconds to define a solidified metallic material having the dimensions of a cast steel alloy crankshaft. Additionally, the method includes separating the solidified metallic material from the sand casting mold to define the cast steel alloy crankshaft.

Description

[0001] Government licensing rights

[0002] This invention was completed with government support under contract number DE-EE0008877 granted by the U.S. Department of Energy. The government holds certain rights to this invention. Technical Field

[0003] This disclosure relates to crankshafts, and more specifically to systems and methods for manufacturing cast steel alloy crankshafts with low porosity for use in vehicles. Background Technology

[0004] A crankshaft is a vehicle component that performs the conversion between reciprocating and rotary motion. Crankshafts can be manufactured in various ways, such as by blanking, forging, and casting. Currently, the manufacturing of cast steel alloy crankshafts can be improved to achieve quality efficiency and cost savings. Summary of the Invention

[0005] Therefore, while current crankshafts have achieved their intended purpose, a new and improved system and method are still needed to manufacture vehicle crankshafts, such as cast steel alloy crankshafts. Based on the embodiments and examples discussed herein, this disclosure provides a system and method for manufacturing vehicle cast steel alloy crankshafts with low porosity. This, in turn, achieves manufacturing cost savings.

[0006] According to one aspect of this disclosure, a method for manufacturing a cast steel alloy crankshaft for an internal combustion engine is provided. The method includes providing a sand casting mold for the crankshaft. The sand casting mold has cavities to form the crankshaft. The crankshaft includes at least three pivot journals and at least four main journals aligned on a crankshaft rotation axis defining a centerline.

[0007] In this respect, each journal pin is arranged around a corresponding journal pin axis and positioned between the main journals. Furthermore, each of the corresponding journal pin axes is oriented parallel to and radially spaced from the crankshaft axis. Each journal pin is connected to a pair of crank arms for force transmission between the journal pin and the pair of crank arms. Additionally, each pair of crank arms is connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal. Furthermore, each crank arm has a counterweight arranged relative to the centerline and opposite the corresponding journal pin for balance and stability.

[0008] In this regard, the method further includes melting a first metallic material at a predetermined temperature (e.g., between 1400 degrees Celsius and 1600 degrees Celsius) to define the molten metallic material. Furthermore, the method further includes feeding the molten metallic material into the cavity of a sand casting mold at a riser connection angle between 30° and 75°.

[0009] The method further includes cooling the molten metal material in the sand casting mold for a predetermined solidification time to define a solidified metal material having the dimensions of the cast steel alloy crankshaft. Additionally, the method includes separating the solidified metal material from the sand casting mold to define the cast steel alloy crankshaft.

[0010] In one example, the solidification time is between 5 and 20 seconds in the sand casting mold to define the solidified metal material. In another example, the solidified metal material has a porosity of less than 10 percent (10%). In yet another example, the solidified metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0011] In this example, the first metallic material comprises 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt% nickel (…). Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0012] In one example, the riser connection angle is between 31° and 65°. In another example, the riser connection angle is between 30° and 55°. In yet another example, the method further includes arranging a cooling component on at least one counterweight of the anodized sand casting mold prior to the feeding step.

[0013] In another aspect of this disclosure, a system for manufacturing a cast steel alloy crankshaft for a vehicle is provided. The system includes a molding unit configured to form a sand casting mold for the cast steel alloy crankshaft. In this respect, the mold includes at least one molding cavity formed therein, the molding cavity having a model having the dimensions of the steel alloy crankshaft. The crankshaft includes at least four main journals aligned on a crankshaft rotation axis defining a centerline and a horizontal plane, the centerline forming through the midpoint of each main journal, and the horizontal plane forming longitudinally along the centerline. The horizontal plane defines a top cut half and a bottom drag half of the mold. The crankshaft further includes at least three pin journals.

[0014] In this respect, each journal pin is arranged around a corresponding journal pin axis and positioned between the main journals. Furthermore, each of the corresponding journal pin axes is oriented parallel to and radially spaced from the crankshaft axis. Additionally, each journal pin is connected to a pair of crank arms for force transmission between the journal pin and the pair of crank arms. Each pair of crank arms is connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal. Moreover, each crank arm has a counterweight arranged relative to the centerline and opposite the corresponding journal pin for balance and stability.

[0015] In this regard, the system further includes a furnace configured to melt a first metallic material at a predetermined temperature (e.g., between 1400°C and 1600°C) to define the molten metallic material. Furthermore, the system further includes a feeding mechanism configured to feed the molten metallic material into at least one cavity of the mold. In this regard, the feeding mechanism includes a riser configured with a connection through which the molten metallic material flows. The connection has a neck in fluid communication with the at least one mold cavity. The connection has an open end configured to flare from the neck into the at least one mold cavity, thereby defining a riser connection angle between 30° and 75° relative to the horizontal plane.

[0016] The system further includes a cooling zone configured to solidify the molten metal material in the sand casting mold for a predetermined solidification time, thereby defining a solidified metal material having the dimensions of the cast steel alloy crankshaft. Furthermore, the system further includes a separation unit configured to separate the solidified metal material from the sand casting mold to define the cast steel alloy crankshaft.

[0017] The system further includes a controller that communicates with the molding unit, the furnace, the feeding mechanism, and the separating unit. The controller is configured to control the molding unit, the furnace, the casting mechanism, and the separating unit. Furthermore, the system includes a power source configured to provide power to the molding unit, the furnace, the feeding mechanism, the separating unit, and the controller.

[0018] In one embodiment, the solidification time is between 5 and 20 seconds, thereby defining the solidified metal material. In another embodiment, the solidified metal material has a porosity of less than 10 percent (10%). In yet another embodiment, the solidified metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0019] In embodiments of this aspect, the first metallic material comprises: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), and at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt% nickel. (Ni), 0.15wt% to 0.55wt% molybdenum (Mo), 0.25wt% to 2.0wt% copper (Cu), at least 0.03wt% titanium (Ti), 0.07wt% to 0.17wt% vanadium (V), 0.02wt% to 0.06wt% aluminum (Al), at least 0.03wt% nitrogen (N), 0.01wt% to 0.06wt% of one of cerium (Ce) and lanthanum (La) and the balance iron (Fe).

[0020] In one embodiment, the riser connection angle is between 31° and 65°. In another embodiment, the riser connection angle is between 30° and 55°. In yet another embodiment, the cooling zone includes a cooling member disposed on at least one counterweight of the anodized sand casting mold. In still another embodiment, the riser is a plurality of risers.

[0021] In another aspect of this disclosure, a cast steel alloy crankshaft for an internal combustion engine is provided. The crankshaft includes at least three journal pins and at least four main journal pins aligned on a crankshaft rotation axis defining a centerline. Each journal pin is arranged around a corresponding journal pin axis and positioned between the main journal pins. Each of the corresponding journal pin axes is oriented parallel to and radially spaced from the crankshaft axis. Each journal pin is connected to a pair of crank arms for force transmission between the journal pins and the pair of crank arms. Each pair of crank arms is connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal. Each crank arm has a counterweight arranged relative to the centerline and opposite the corresponding journal pin for balance and stability.

[0022] In this respect, each main journal and each pin journal comprises a first metallic material having a porosity of less than 15 percent. The first metallic material comprises 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt% nickel (Ni). 0.15 wt% to 0.55 wt% of molybdenum (Mo), 0.25 wt% to 2.0 wt% of copper (Cu), at least 0.03 wt% of titanium (Ti), 0.07 wt% to 0.17 wt% of vanadium (V), 0.02 wt% to 0.06 wt% of aluminum (Al), at least 0.03 wt% of nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0023] In one embodiment, the first metallic material has a porosity of less than 10 percent. In another embodiment, the first metallic material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) of greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0024] 1. A method for manufacturing a cast steel alloy crankshaft for an internal combustion engine, the method comprising:

[0025] A sand casting mold is provided for the crankshaft, the sand casting mold having a cavity for forming the crankshaft, the crankshaft comprising:

[0026] At least four main journals aligned on the crankshaft rotation axis defining the center line; and

[0027] At least three journals, each journal being arranged around a corresponding journal axis and positioned between the main journals, each of the corresponding journal axes being oriented parallel to and radially spaced from the crankshaft axis, each journal being connected to a pair of crank arms for force transmission between the journals and the pair of crank arms, each pair of crank arms being connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal, each crank arm having a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability;

[0028] Melt the first metallic material at a predetermined temperature to confine the molten metallic material;

[0029] The molten metal material is fed into the cavity of the anodized sand casting mold at a riser connection angle between 30° and 75°;

[0030] The molten metal material is cooled in the sand casting mold for a predetermined solidification time to define a solidified metal material having the dimensions of the cast steel alloy crankshaft; and

[0031] The solidified metal material is separated from the sand casting mold to define the cast steel alloy crankshaft.

[0032] 2. The method according to Scheme 1, wherein the predetermined solidification time is between 5 seconds and 20 seconds in the anodized sand casting mold to define the solidified metal material.

[0033] 3. The method according to Scheme 1, wherein the solidified metal material has a porosity of less than 10 percent (10%).

[0034] 4. The method according to Scheme 1, wherein the solidified metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0035] 5. The method according to Scheme 1, wherein the first metallic material comprises: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), and at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt% sulfur (S). The composition comprises nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0036] 6. The method according to Scheme 1, wherein the riser connection angle is between 31° and 65°.

[0037] 7. The method according to Scheme 1, wherein the riser connection angle is between 30° and 55°.

[0038] 8. The method according to Scheme 1, further comprising:

[0039] Prior to the feeding step, a cooling component is placed on at least one counterweight of the anodized sand casting mold.

[0040] 9. A system for manufacturing a cast steel alloy crankshaft for a vehicle, the system comprising:

[0041] A molding unit configured to form a sand casting mold for the cast steel alloy crankshaft, the mold including at least one molding cavity having a model having the dimensions of the steel alloy crankshaft, the crankshaft comprising:

[0042] At least four main journals are aligned on the crankshaft rotation axis defining a centerline and a horizontal plane, the centerline being formed through the midpoint of each main journal, and the horizontal plane being formed longitudinally along the centerline, the horizontal plane defining the upper cut half and the lower pull half of the mold; and

[0043] At least three journals, each journal being arranged around a corresponding journal axis and positioned between the main journals, each of the corresponding journal axes being oriented parallel to and radially spaced from the crankshaft axis, each journal being connected to a pair of crank arms for force transmission between the journals and the pair of crank arms, each pair of crank arms being connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal, each crank arm having a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability;

[0044] A furnace configured to melt a first metallic material at a predetermined temperature to define the molten metallic material;

[0045] A feeding mechanism configured to feed the molten metal material into at least one cavity of the mold, the feeding mechanism including a riser configured with a connection through which the molten metal material flows, the connection having a neck in fluid communication with the at least one mold cavity, the connection having an open end configured to flare from the neck to the at least one mold cavity, thereby defining a riser connection angle between 30° and 75° relative to the horizontal plane;

[0046] A cooling zone is provided to allow the molten metal material to solidify in the anodized sand casting mold for a predetermined solidification time, thereby defining a solidified metal material having the dimensions of the cast steel alloy crankshaft.

[0047] A separation unit is configured to separate the solidified metal material from the anodized mold to define the cast steel alloy crankshaft;

[0048] A controller communicating with the molding unit, the furnace, the feeding mechanism, and the separating unit, wherein the controller is configured to control the molding unit, the furnace, the casting mechanism, and the separating unit; and

[0049] A power source is configured to provide power to the molding unit, the furnace, the feeding mechanism, the separating unit, and the controller.

[0050] 10. The system according to claim 9, wherein the predetermined solidification time is between 5 seconds and 20 seconds, thereby defining the solidified metal material.

[0051] 11. The system according to Scheme 9, wherein the solidified metal material has a porosity of less than 10 percent (10%).

[0052] 12. The system according to Scheme 9, wherein the solidified metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0053] 13. The system according to claim 9, wherein the first metallic material comprises: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), and at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt% sulfur (S). The composition comprises nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0054] 14. The system according to Scheme 9, wherein the riser connection angle is between 31° and 65°.

[0055] 15. The system according to Scheme 9, wherein the riser connection angle is between 30° and 55°.

[0056] 16. The system according to claim 9, wherein the cooling zone includes a cooling component disposed on at least one counterweight of the anodized sand casting mold.

[0057] 17. The system according to Scheme 9, wherein the riser is a plurality of risers.

[0058] 18. A cast steel alloy crankshaft for an internal combustion engine, the crankshaft comprising:

[0059] At least four main journals aligned on the crankshaft rotation axis defining the center line; and

[0060] At least three journals are provided, each journal arranged around a corresponding journal axis and positioned between the main journals. Each of the corresponding journal axes is oriented parallel to and radially spaced from the crankshaft axis. Each journal is connected to a pair of crank arms for force transmission between the journals and the pair of crank arms. Each pair of crank arms is connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal. Each crank arm has a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability.

[0061] Each main journal and each pin journal comprises a first metallic material having a porosity of less than 15 percent and comprising: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), and 0.8 wt% to 1.4 wt% chromium (Cr). 0.2 wt% to 0.6 wt% nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0062] 19. The crankshaft according to claim 18, wherein the first metallic material has a porosity of less than 10 percent.

[0063] 20. The crankshaft according to Scheme 18, wherein the first metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) greater than 750 MPa, and an elongation (EL) of 5% to 10%.

[0064] Further applications will become apparent from the description provided herein. It should be understood that the descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0065] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0066] Figure 1This is a schematic diagram of a system for manufacturing a cast steel alloy crankshaft with low porosity for a vehicle, according to an embodiment of the present disclosure.

[0067] Figure 2 According to one embodiment, by Figure 1 A side view of the crankshaft manufactured by the system.

[0068] Figure 3 It is a section taken along line 3-3. Figure 2 A cross-sectional view of the crankshaft.

[0069] Figure 4 yes Figure 2 A top perspective view of the crankshaft.

[0070] Figure 5 yes Figure 4 End view of the crankshaft.

[0071] Figure 6 According to one embodiment Figure 1 A top view of the system's feed mechanism.

[0072] Figure 7A It is a section taken along line 7-7. Figure 6 A cross-sectional side view of the riser of the feeding mechanism in the middle.

[0073] Figure 7B It is based on an example Figure 6 A table showing the riser connection angles for multiple risers.

[0074] Figure 8 yes Figure 6 A perspective view of the cooling components of the feeding mechanism.

[0075] Figure 9A yes Figure 6 Side view of the feeding mechanism in the middle.

[0076] Figure 9B yes Figure 9A A table of solidification times for cooling components.

[0077] Figure 10 This is based on an example of the present disclosure. Figure 1 The flowchart shows the method for manufacturing cast steel alloy crankshafts using the system. Detailed Implementation

[0078] The following description is exemplary in nature and is not intended to limit this disclosure, its application or use.

[0079] Figure 1 An embodiment of the present disclosure is shown for manufacturing a cast steel alloy crankshaft 110 with low porosity for use in a vehicle. Figure 2System 10. As shown, this system 10 includes a molding unit 12, which is configured to have a sand casting mold 30 with a cast steel alloy crankshaft 110 (see Figure 9A The mold 30 includes at least one molding cavity, preferably multiple molding cavities, to define the crankshaft to be cast. The molding unit 12 is configured such that the mold 30 has a model having the dimensions of the crankshaft. In one example, the mold 30 has a model made using wet sand or chemically bonded sand. Core assemblies can then be arranged within the mold to further define the dimensions or structure of the model. It should be understood that the mold can be manufactured by any other suitable means without departing from the spirit or scope of this disclosure.

[0080] Refer to the example Figure 2-3 The crankshaft 110 is designed or configured to include at least four main journals 112 aligned on a crankshaft rotation axis 114 that defines a centerline 116 and a horizontal plane H. As shown, the centerline 116 is formed through the midpoint 117 of each main journal 112, and the horizontal plane H is formed longitudinally along the centerline 116. The horizontal plane H defines an upper tangent half 118 and a lower tangent half 119 of the crankshaft 110.

[0081] The crankshaft 110 is designed or configured to include at least three journals 120. As shown, each journal 120 is arranged around a corresponding journal axis 122 and positioned between main journals 112. Furthermore, each journal axis 122 is oriented parallel to and radially spaced from the crankshaft axis 114. Additionally, each of the journals 120 is connected to a pair of crank arms 124 for force transmission between the journal 120 and the pair of crank arms 124. Furthermore, each pair of crank arms 124 is connected to a corresponding main journal 112 for torque transmission between the pair of crank arms 124 and the main journal 112. Moreover, each of the main journals 112, journals 120, and crank arms 124 is made of a first metallic material.

[0082] As an example Figure 2 and Figure 3 As shown, at least one of the crank arms 124 is configured to have a molded counterweight 130. Furthermore, each molded counterweight 130 is arranged opposite the corresponding pin journal 120 relative to the centerline 116 for balance and stability. The counterweight 130 is molded into one of the crank arms during the manufacture of the crankshaft 110.

[0083] In one embodiment, the first metallic material comprises a steel alloy having a rare earth metal such as cerium or lanthanum. Preferably, the first metallic material is made of a composition comprising 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt%... Nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0084] More preferably, the first metallic material comprises: 0.35 wt% C, 0.45 wt% Si, 1.0 wt% Mn, at least 0.03 wt% P, 0.06 wt% S, 1.0 wt% Cr, 0.2 wt% Ni, 0.25 wt% Mo, 0.45 wt% Cu, at least 0.03 wt% Ti, 0.1 wt% V, 0.03 wt% Al, at least 0.03 wt% N, 0.02 wt% Ce and La, and the balance being Fe.

[0085] In another embodiment, the first metal material of the crankshaft has a porosity of less than 15 percent (15%) and preferably less than 10 percent. Moreover, the first metal material has an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) of greater than 750 MPa, and an elongation (EL) of 5 percent to 10 percent.

[0086] Return to reference Figure 1 The system 10 further includes a furnace 14 for melting a first metallic material (e.g., a steel alloy) between 1400 degrees Celsius (°C) and 1600 degrees Celsius to define the molten metallic material. In one embodiment, the furnace 14 may be filled with a steel alloy. The furnace 14 may be an electric arc furnace, an induction furnace, or any other suitable furnace without departing from the spirit or scope of this disclosure.

[0087] like Figure 1 and Figure 6As shown, system 10 further includes a feeding mechanism 16 configured to feed molten metal material into at least one cavity of a mold 30 defining the dimensions of the crankshaft 110 to be cast. In one example, the feeding mechanism 16 includes a ladle (not shown), a bottom gate 31, a filter 32 in fluid communication with the bottom gate 31, a runner 34 in fluid communication with the bottom gate 31, and at least one riser in fluid communication with the runner and the at least one cavity of the mold. In this example, the feeding mechanism 16 includes a plurality of risers R1-R10, such as... Figure 6 As shown.

[0088] In this example, the ladle receives molten metal (e.g., a steel alloy) for pouring into a bottom gate 31 with a filter 32 to remove oxides from the molten metal. As mentioned, the bottom gate 31 is in fluid communication with a runner 34 (here, a double runner with first and second flanges 36, 38), through which the molten metal flows from the filter 32. As shown, the runner 34 is connected to risers R1-R10, allowing molten metal to be fed into the risers. Thus, the runner 34 is configured to be in fluid communication with the risers R1-R10 to which the molten metal is fed.

[0089] like Figure 6-7A As shown, each riser (e.g., riser R3) is configured to have a connection portion 42 through which molten metal material flows. The connection portion 42 has a neck 44 in fluid communication with the at least one mold cavity. Figures 7A-7B As shown, the neck 44 is configured to flare or extend from the wall 46 of the connection portion 42 toward the mold 30. Furthermore, the neck 44 extends to the inner base 48, which is configured to extend toward the mold 30, for example, on an inclined portion. As shown, the neck 44 and the inner base 48 extend to an opening end 49 through which molten metal material can pass into the mold 30. Furthermore, the neck 44 and the inner base 48 define a general riser connection angle between 30° and 75° relative to a horizontal plane. In one embodiment, the general riser connection angle is between 31° and 65°. In another embodiment, the general riser connection angle is between 30° and 55°.

[0090] refer to Figure 6-7B The neck 44 defines a first riser connection angle A1 relative to the horizontal plane H, and the inner base 48 defines a second riser connection angle A2 relative to the horizontal plane H. For example... Figure 7BAs can be seen, each of risers R1-R10 has a first and a second riser connection angle A1 and A2, where each connection angle can vary depending on the crankshaft size. For example, riser R4 has a first riser connection angle A1 of 30° and a second riser connection angle A2 of 1°. Thus, riser R4 has an overall riser connection angle of 31°. However, riser R5 has a first riser connection angle A1 of 45° and a second riser connection angle A2 of 10°. Thus, riser R5 has an overall riser connection angle of 55°.

[0091] The mold 30 can then be sealed or sealed with chemically bonded sand. Subsequently, the molten metal is allowed to cool to approximately 450°C in a designated cooling zone (discussed below) to solidify the molten metal in multiple molding cavities of the mold to form the target component having the dimensions of a crankshaft. Preferably, the crankshaft is made of a steel alloy comprising the components discussed above.

[0092] Additionally, system 10 further includes a cooling zone 17 configured to solidify the molten metal material. Thus, the cooling zone 17 solidifies the molten metal material in the anodized sand casting mold for a solidification time between 5 and 20 seconds, defining a solidified metal material having the dimensions of the cast steel alloy crankshaft 110. In another embodiment, the solidification time is between 10 and 15 seconds, thereby defining the solidified metal material.

[0093] To achieve the desired solidification time range, cooling zone 17 may include a cooling component arranged on at least one counterweight of the sand casting mold. For example... Figure 8 As shown, the cooling component 50 is arranged on the counterweight 130 of the mold 30. When molten metal is fed into the cavity of the mold 30, the cooling component 50 provides a more rapid cooling effect to solidify the molten metal into solidified metal.

[0094] refer to Figures 9A-9B Before feeding molten metal into the mold, cooling members 1'-12' are arranged on the corresponding counterweight portions CW1-CW12 of the mold 30. As described above, cooling members 1'-12' provide more rapid solidification of the molten metal to define the solidified metal. The solidification time can vary. For example, cooling member 1' is arranged on the counterweight at position CW1, resulting in a solidification time of 6 seconds when the molten metal is fed into the mold. However, cooling member 3' is arranged on the counterweight at position CW3, resulting in a solidification time of 8 seconds when the molten metal is fed into the mold.

[0095] Return to reference Figure 1System 10 further includes a separation unit 18 for separating the target component of the crankshaft from the sand casting mold to define the cast steel alloy crankshaft 110. In one embodiment, the separation unit 18 is configured to shake off or remove the mold comprising chemically bonded sand from the target component. To accomplish the removal of the mold from the target component, an automated unit may be used to break the mold and thereby obtain the target component. For example, a vibration unit or table may be used having a bottom-capturing filter for receiving mold particles from the mold. It should be understood that any other suitable means of breaking the mold may be used without departing from the spirit or scope of this disclosure.

[0096] In this embodiment, the separation unit 18 is further configured to remove the gate from the target part after the mold has been removed from the target part. As is known in the art, removing the gate from the target part may include removing the portion of the adhesive sand used to fill the mold during casting and pouring.

[0097] In one embodiment, the separation unit 18 is further configured to clean the target part after the gate is removed. In one example, a shot blasting machine may be used to apply or blast shot (e.g., metal shot) onto the surface of the target part. To meet alloy design expectations, the separation unit 18 may also include an inspection area in which the mechanical dimensions, mechanical properties, chemical composition, and microstructure of the target part are examined. In one example, a computerized system such as a coordinate measuring machine (CMM) may be used to measure the mechanical dimensions of the target part, thereby defining the crankshaft 110. Any suitable methods and equipment may be used to evaluate the dimensions, mechanical properties, chemical composition, and microstructure of the crankshaft without departing from the spirit or scope of this disclosure.

[0098] Return to reference Figure 1 The system 10 further includes at least one controller 20 that communicates with the molding unit 12, the furnace 14, the feeding mechanism 16, and the separating unit 18. The controller 20 is configured to control the molding unit 12, the furnace 14, the feeding mechanism 16, and the separating unit 18. Furthermore, the system 10 includes a power source 22 configured to provide power to the molding unit 12, the furnace 14, the feeding mechanism 16, the separating unit 18, and the controller 20.

[0099] Figure 10 A method 210 for manufacturing a cast steel alloy crankshaft with low porosity for a vehicle, according to an example of this disclosure, is shown. In this example, method 210 may be manufactured by... Figure 1 The system is implemented as described above. As shown, method 210 includes providing a sand casting mold for a cast steel alloy crankshaft in block 212. As discussed above and as... Figure 2-5As shown, the crankshaft 110 is designed or configured to include at least four main journals 112 aligned on the crankshaft rotation axis 114 defining a centerline 116. As shown, the centerline 116 is formed through the midpoint 117 of each main journal 112, and a horizontal plane H is formed longitudinally along the centerline 116. As shown, the horizontal plane H defines an upper cut-off portion 118 and a lower cut-off portion 119. The crankshaft 110 further includes at least three pivot journals 120.

[0100] In this embodiment, each journal pin 120 is arranged around a corresponding journal pin axis 122 and positioned between main journal pins 112. Furthermore, each journal pin axis 122 is oriented parallel to and radially spaced from the crankshaft axis 114. Additionally, each of the journal pins 120 is connected to a pair of crank arms 124 for force transmission between the journal pin 120 and the pair of crank arms 124. Moreover, each pair of crank arms 124 is connected to a corresponding main journal pin 112 for torque transmission between the pair of crank arms 124 and the main journal pin 112.

[0101] As an example Figure 2-5 As shown, at least one of the crank arms 124 is configured to have a counterweight 130. Furthermore, each molded counterweight 130 is arranged opposite the corresponding pivot journal 120 relative to the centerline 116 for balance and stability. During the manufacture of the crankshaft 110, the counterweight 130 is molded together with the at least one of the crank arms. Additionally, each of the main journal 112, pivot journal 120, counterweight, and crank arm 124 is made of the first metallic material discussed above.

[0102] Furthermore, in this example, method 210 further includes melting a first metallic material in block 214 between 1400 degrees Celsius (°C) and 1600°C to define the molten metallic material. In one example, the first metallic material may be melted by the furnace 14 discussed above. The furnace may be an electric arc furnace, an induction furnace, or any other suitable furnace without departing from the spirit or scope of this disclosure.

[0103] Method 210 further includes feeding molten metal material in the cavity of the sand casting mold at a riser connection angle between 30° and 75° within frame 216. In another example, the riser connection angle is between 31° and 65°. In yet another example, the riser connection angle is between 30° and 55°. The feeding step can be accomplished by the feeding mechanism 16 discussed above to feed molten metal material into said at least one cavity of the mold defining the dimensions of the crankshaft 110 to be cast. As discussed above, the feeding mechanism 16 includes a ladle (not shown), a bottom gate 31, a filter 32 in fluid communication with the bottom gate 31, a sprue 34 in fluid communication with the filter 32 and the bottom gate 31, and risers R1-R10 in fluid communication with the sprue 34 and said at least one cavity of the mold 30.

[0104] In this example, the ladle receives molten metal (e.g., a steel alloy) for pouring into a bottom gate 31 with a filter 32 to remove oxides from the molten metal. As mentioned, the bottom gate 31 is in fluid communication with a runner 34 through which the molten metal flows. As shown, the runner 34 is connected to risers R1-R10, allowing molten metal to be fed into the risers. Thus, the runner 34 is configured to be in fluid communication with risers R1-R10, through which molten metal is fed in the cavity of the sand casting mold at an overall riser connection angle between 30° and 75°. In one example, the riser connection angle is between 31° and 65°. In another example, the riser connection angle is between 30° and 55°.

[0105] As shown, method 210 further includes cooling or solidifying molten metal material in a sand casting mold within frame 220 for a solidification time between 5 and 20 seconds to define a solidified metal material having the dimensions of a cast steel alloy crankshaft. The solidification step can be accomplished via the cooling zone 17 discussed above to solidify the molten metal material into a solidified metal material. In another example, the solidification time is between 10 and 15 seconds, thereby defining the solidified metal material. To achieve the desired solidification time range, the cooling zone 17 may include a cooling member arranged on at least one counterweight of the sand casting mold. The solidification step may include allowing the molten metal material to cool to approximately 450°C.

[0106] Alternatively, the method may include cooling the component (see [link to method]) prior to the feeding step. Figure 8 It is placed on at least one counterweight of the sand casting mold to cool the molten metal material at the required solidification time.

[0107] In one example, the solidified metal material has a porosity of less than 10 percent (10%), an ultimate tensile strength (UTS) of 900 MPa to 1200 MPa, a yield strength (YS) of greater than 750 MPa, and an elongation (EL) of 5 percent to 10 percent.

[0108] Method 210 further includes separating the solidified metal material from the sand casting mold in frame 222 to define the cast steel alloy crankshaft. Figure 1 As shown in System 10, in order to complete the removal of the mold from the cast crankshaft, an automatic unit is used to break the mold and thereby obtain the cast steel alloy crankshaft. For example, a vibration unit or table may be used, having a bottom-capturing filter for receiving mold particles from the mold. It should be understood that, without departing from the spirit or scope of this disclosure, mold breaking can be achieved by any suitable means, such as a vibration unit.

[0109] In this example, the separation step may include removing the gate from the target crankshaft casting after removing the mold from the crankshaft and cleaning the target crankshaft casting after removing the gate. Figure 1 As in System 10, a shot blasting machine can be used to apply or spray metal shot onto the surface of a target crankshaft casting. To meet design expectations, the separation unit may also include an inspection area where the dimensions, mechanical properties, chemical composition, and microstructure of the target crankshaft casting are examined. For example, a computerized system such as a CMM can be used to measure the mechanical dimensions of the target crankshaft, thereby defining the crankshaft of this disclosure. Any suitable methods and equipment can be used to evaluate the mechanical dimensions, mechanical properties, chemical composition, and microstructure of a crankshaft without departing from the spirit or scope of this disclosure.

[0110] In one example, the first metallic material comprises a steel alloy. In another example, the first metallic material has the following composition: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), and 0.2 wt% to 0.6 wt%... Nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

[0111] More preferably, the first metallic material comprises: 0.35 wt% C, 0.45 wt% Si, 1.0 wt% Mn, at least 0.03 wt% P, 0.06 wt% S, 1.0 wt% Cr, 0.2 wt% Ni, 0.25 wt% Mo, 0.45 wt% Cu, at least 0.03 wt% Ti, 0.1 wt% V, 0.03 wt% Al, at least 0.03 wt% N, 0.02 wt% Ce and La, and the balance being Fe.

[0112] The description in this disclosure is merely exemplary in nature, and variations thereof that do not depart from the essential points of this disclosure are intended to fall within its scope. Such variations should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A method for manufacturing a cast steel alloy crankshaft for an internal combustion engine, the method comprising: A sand casting mold is provided for the crankshaft, the sand casting mold having a cavity for forming the crankshaft, the crankshaft comprising: At least four main journals aligned on the crankshaft rotation axis defining the center line; and At least three journals, each journal being arranged around a corresponding journal axis and positioned between the main journals, each of the corresponding journal axes being oriented parallel to and radially spaced from the crankshaft rotation axis, each journal being connected to a pair of crank arms for force transmission between the journals and the pair of crank arms, each pair of crank arms being connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal, each crank arm having a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability; Melt the first metallic material at a predetermined temperature to confine the molten metallic material; The molten metal material is fed into the cavity of the anodized sand casting mold at a riser connection angle between 30° and 75°; The molten metal material is cooled in the sand casting mold for a predetermined solidification time to define a solidified metal material having the dimensions of the cast steel alloy crankshaft; and The solidified metal material is separated from the sand casting mold to define the cast steel alloy crankshaft. The predetermined solidification time is between 5 and 20 seconds in the anodized sand casting mold to define the solidified metal material.

2. The method of claim 1, wherein, The solidified metal material has a porosity of less than 10 percent.

3. The method of claim 1, wherein, The solidified metal material has an ultimate tensile strength of 900 MPa to 1200 MPa, a yield strength of greater than 750 MPa, and an elongation of 5% to 10%.

4. The method of claim 1, wherein, The first metallic material comprises: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), and at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), 0.2 wt% to 0.6 wt% nickel (Ni), and 0. 0.15 wt% to 0.55 wt% of molybdenum (Mo), 0.25 wt% to 2.0 wt% of copper (Cu), at least 0.03 wt% of titanium (Ti), 0.07 wt% to 0.17 wt% of vanadium (V), 0.02 wt% to 0.06 wt% of aluminum (Al), at least 0.03 wt% of nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

5. The method of claim 1, wherein, The riser connection angle is between 31° and 65°.

6. The method of claim 1, wherein, The riser connection angle is between 30° and 55°.

7. The method of claim 1, further comprising: Prior to the feeding step, a cooling component is placed on at least one counterweight of the anodized sand casting mold.

8. A system for manufacturing a cast steel alloy crankshaft for a vehicle, the system comprising: A molding unit configured to form a sand casting mold for the cast steel alloy crankshaft, the mold including at least one molding cavity having a model having the dimensions of the steel alloy crankshaft, the crankshaft comprising: At least four main journals are aligned on the crankshaft rotation axis defining a centerline and a horizontal plane, the centerline being formed through the midpoint of each main journal, and the horizontal plane being formed longitudinally along the centerline, the horizontal plane defining the upper cut half and the lower pull half of the mold; and At least three journals, each journal being arranged around a corresponding journal axis and positioned between the main journals, each of the corresponding journal axes being oriented parallel to and radially spaced from the crankshaft rotation axis, each journal being connected to a pair of crank arms for force transmission between the journals and the pair of crank arms, each pair of crank arms being connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal, each crank arm having a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability; A furnace configured to melt a first metallic material at a predetermined temperature to define the molten metallic material; A feeding mechanism configured to feed the molten metal material into at least one cavity of the mold, the feeding mechanism including a riser configured with a connection through which the molten metal material flows, the connection having a neck in fluid communication with the at least one mold cavity, the connection having an open end configured to flare from the neck to the at least one mold cavity, thereby defining a riser connection angle between 30° and 75° relative to the horizontal plane; A cooling zone is provided to allow the molten metal material to solidify in the anodized sand casting mold for a predetermined solidification time, thereby defining a solidified metal material having the dimensions of the cast steel alloy crankshaft. A separation unit is configured to separate the solidified metal material from the anodized mold to define the cast steel alloy crankshaft; A controller communicating with the molding unit, the furnace, the feeding mechanism, and the separating unit, wherein the controller is configured to control the molding unit, the furnace, the feeding mechanism, and the separating unit; and A power source, configured to provide power to the molding unit, the furnace, the feeding mechanism, the separating unit, and the controller. The predetermined solidification time is between 5 seconds and 20 seconds, thereby defining the solidified metal material.

9. The system of claim 8, wherein, The solidified metal material has a porosity of less than 10 percent.

10. The system of claim 8, wherein, The solidified metal material has an ultimate tensile strength of 900 MPa to 1200 MPa, a yield strength of greater than 750 MPa, and an elongation of 5% to 10%.

11. The system of claim 8, wherein, The first metallic material comprises: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), and at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), 0.2 wt% to 0.6 wt% nickel (Ni), and 0. 0.15 wt% to 0.55 wt% of molybdenum (Mo), 0.25 wt% to 2.0 wt% of copper (Cu), at least 0.03 wt% of titanium (Ti), 0.07 wt% to 0.17 wt% of vanadium (V), 0.02 wt% to 0.06 wt% of aluminum (Al), at least 0.03 wt% of nitrogen (N), 0.01 wt% to 0.06 wt% of one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

12. The system of claim 8, wherein, The riser connection angle is between 31° and 65°.

13. The system of claim 8, wherein, The riser connection angle is between 30° and 55°.

14. The system of claim 8, wherein, The cooling zone includes a cooling component arranged on at least one counterweight of the anodized sand casting mold.

15. The system of claim 8, wherein, The riser refers to multiple risers.

16. A cast steel alloy crankshaft for an internal combustion engine manufactured by the method according to any one of claims 1 to 7, the crankshaft comprising: At least four main journals aligned on the crankshaft rotation axis that defines the center line; and At least three journals are provided, each journal arranged around a corresponding journal axis and positioned between the main journals. Each of the corresponding journal axes is oriented parallel to and radially spaced from the crankshaft rotation axis. Each journal is connected to a pair of crank arms for force transmission between the journals and the pair of crank arms. Each pair of crank arms is connected to a corresponding main journal for torque transmission between the pair of crank arms and the main journal. Each crank arm has a counterweight arranged relative to the centerline and opposite the corresponding journal for balance and stability. Each main journal and each pin journal comprises a first metallic material having a porosity of less than 15 percent and comprising: 0.29 wt% to 0.65 wt% carbon (C), 0.40 wt% to 0.80 wt% silicon (Si), 0.6 wt% to 1.5 wt% manganese (Mn), at least 0.03 wt% phosphorus (P); 0.04 wt% to 0.07 wt% sulfur (S), 0.8 wt% to 1.4 wt% chromium (Cr), 0 0.2 wt% to 0.6 wt% nickel (Ni), 0.15 wt% to 0.55 wt% molybdenum (Mo), 0.25 wt% to 2.0 wt% copper (Cu), at least 0.03 wt% titanium (Ti), 0.07 wt% to 0.17 wt% vanadium (V), 0.02 wt% to 0.06 wt% aluminum (Al), at least 0.03 wt% nitrogen (N), 0.01 wt% to 0.06 wt% one of cerium (Ce) and lanthanum (La), and the balance being iron (Fe).

17. The crankshaft of claim 16, wherein, The first metallic material has a porosity of less than 10 percent.

18. The crankshaft of claim 16 wherein, The first metallic material has an ultimate tensile strength of 900 MPa to 1200 MPa, a yield strength of greater than 750 MPa, and an elongation of 5% to 10%.

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