A casting process for a round tube-shaped cast steel

Abstract

The patent introduces a kind of round pipe steel casting process method, the specific steps are as follows: S1: according to the product structure of round pipe casting, the scheme of horizontal placement of round pipe casting is adopted for pouring;S2: the pouring system adopts open type, the ingate is arranged at the end of the casting;S3: the feeding channel is designed;S4: the riser is designed;S5: according to the design of S1-S4, the sand box molding is adopted, and the casting is poured after the box is closed.The invention solves the problem that the riser of the casting is difficult to cut, maximally reduces the cutting phenomenon of the casting, improves the surface quality of the casting, and the casting completely meets the requirements of ultrasonic flaw detection after machining;The setting of the sand accumulation groove is beneficial to enhance the sequential solidification of the casting;The process method of the invention has high overall compatibility, saves raw materials, reduces the cutting workload of the casting, reduces the polishing and finishing workload of the casting surface, and improves the production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting process, in particular to a casting process method of round pipe-shaped cast steel parts. BACKGROUND

[0002] In actual production, large cast steel parts often have round pipe-shaped castings, i.e. tubular parts, which have high quality requirements, full machining, and require full ultrasonic flaw detection inspection. However, the structure and shape of the castings do not meet the feeding conditions of the cast steel parts. Therefore, only the feeding of the castings can be set on the outer circle or the inner circle of the castings to facilitate the feeding of the castings by the riser, so as to meet the feeding requirements of the castings during the cooling and solidification process. However, in the post-processing process, the riser feeding is removed by gas cutting. Due to the curved surface, it is not convenient to cut in place, resulting in large machining allowance and overweight of the castings, and the castings are easily cut.

[0003] Therefore, for such products, how to reduce or eliminate the riser feeding, i.e. reduce or eliminate the hidden danger of gas cutting of the castings, improve the surface quality, reduce the production cost, and improve the work efficiency is particularly important. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, provide a casting process method of round pipe-shaped cast steel parts, which can reduce or eliminate the hidden danger of gas cutting of the castings, and improve the production efficiency.

[0005] The technical solution adopted by the present application is:

[0006] A casting process method of round pipe-shaped cast steel parts, the specific steps are:

[0007] S1: According to the product structure of the round pipe-shaped castings, the casting process method adopts the scheme of horizontally placing the round pipe-shaped castings for pouring, and the parting and molding are performed at the horizontal center of the outer circle of the round pipe-shaped castings;

[0008] S2: The pouring system adopts an open type, and the cross section ratio is as follows: hole: sprue: runner: ingate = 1: (1.8-2.0): (1.8-2.0): (2.0-2.5); The inner gate is arranged at the end of the casting and located at a position 60-100 mm below the parting surface;

[0009] S3: Feeding channel design:

[0010] a: The castings are fully machined, and the machining allowance is placed according to the standard. The center of the inner circle of the castings is offset downward, and the offset value is half of the machining allowance, forming a feeding channel with thick upper part and thin lower part in sequence;

[0011] b: The riser feeding is arranged on the upper half of the outer circle of the castings, and the outer circle machining allowance of 2 / 3 of the outer circle is gradually added to the lower part of the outer circle to the transition to 0 at both ends of the upper box parting surface, and the feeding length is made as a whole with the length of the castings;

[0012] c: set the sand accumulation groove along the length of the outer circle of the casting, and strengthen the feeding sequence;

[0013] d. Set a row of external chill along the length of the lower part of the outer circle of the casting, the width of the external chill is in the range of the corresponding angle a = 40°-55° of the outer circle, and the thickness is 1-1.2 times the wall thickness of the casting;

[0014] S4: riser design: the riser is arranged at the uppermost part of the outer circle of the casting, and the size and shape of the riser are determined by using the modulus method according to M 冒 ≥1.2M 件 ;

[0015] Wherein, M 冒 =V 冒 / A 冒 , M 冒 is the riser modulus, V 冒 is the riser volume, and A 冒 is the riser surface area; M 件 =V 件 / A 件 , M 件 is the casting modulus, V 件 is the casting volume, and A 件 is the casting heat dissipation surface area;

[0016] The number of risers is determined according to the feeding distance; the riser area = 4M 件 ; and the end area = 5M 件 ;

[0017] The riser checking is performed according to the feeding liquid amount method, η*G 冒 ≥(G 件 +G 冒 )*ε checking; G 冒 is the weight of the riser; G 件 is the weight of the casting of the feeding part of the riser; η is the feeding efficiency of the riser; and ε is the volume shrinkage rate of the metal liquid;

[0018] S5: according to the design of S1-S4, sand box molding is adopted, the outer shape is divided into upper and lower box molds, the inner hole is made into an integral sand core, the core heads are arranged at both ends, and pouring is performed after the box is closed.

[0019] Specifically, the surface sand layer thickness of the mold is set to 50-120mm.

[0020] Specifically, the surface sand layer thickness around the gate is set to 100-150mm.

[0021] Specifically, the external chill and the mold are separated by chromite sand with a separation sand thickness of 10-20mm.

[0022] Due to the adoption of the technical solutions described above, the present application has the following advantages:

[0023] The present application adopts the inner hole eccentricity, the gradual transition of the machining allowance of the upper half of the outer circle and the multiple feeding channel superposition cooperation of the sand accumulation groove at the top and the use of the outer cooling iron at the bottom of the outer circle, effectively reduces the riser feeding, when cutting the riser feeding during the post-processing of the casting, the inner hole eccentricity does not need to be cut, the outer circle only needs to be cut horizontally to remove the machining allowance height added by the superposition of the sand accumulation groove at the top, the remaining transition machining allowance of the upper half of the outer circle is small, which is included in the weight of the casting and is not removed, thereby solving the problem that the riser feeding of the casting is difficult to cut, minimizing the cutting of the casting, improving the surface quality of the casting, and the casting after machining fully meets the requirements of ultrasonic flaw detection; the setting of the sand accumulation groove makes the gas and impurities in the cavity float to the sand accumulation groove during pouring, and increases the thickness of the top of the casting, further strengthens the temperature gradient from top to bottom, and is beneficial to enhancing the sequential solidification of the casting; the process method of the present application has high overall cooperation degree, saves raw materials, reduces the cutting workload of the casting and the polishing and finishing workload of the surface of the casting, and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 is a sectional view of the present application.

[0025] Fig. 2 is a schematic view of the end face of the casting of the present application.

[0026] Fig. 3 is a schematic view of the riser feeding distance of the present application.

[0027] In the figure: 1-casting, 2-riser feeding, 3-sand accumulation groove, 4-riser, 5-outer cooling iron, 6-pouring system, 61-inner gate. DETAILED DESCRIPTION

[0028] The present application will be further explained and described below in combination with the drawings and examples, which cannot limit the protection scope of the present application, and the purpose of disclosing the present application is to protect all technical improvements within the scope of the present application.

[0029] In combination with the drawings Figs. 1-3 The casting process method of a round pipe-shaped cast steel part is specifically as follows:

[0030] S1: According to the product structure of the round pipe-shaped casting 1, the scheme of horizontally placing the round pipe-shaped casting 1 for pouring is adopted, and the parting and molding are performed at the horizontal center of the outer circle of the round pipe-shaped casting 1.

[0031] S2: The pouring system 6 adopts an open type, and the cross section ratio is 1:1.8:2:2 for the hole: the sprue: the runner: the inner gate; the inner gate 61 is arranged at the end of the casting 1 and located at the position 60-100mm below the parting surface.

[0032] S3: The feeding channel design:

[0033] a: the casting 1 is fully machined, the machining allowance is placed according to the standard, the center of the inner circle of the casting 1 is offset downward, the offset value is half of the machining allowance, forming a feeding channel of sequential solidification with thick upper and thin lower;

[0034] b: the riser pad 2 is arranged on the upper half of the outer circle of the casting 1, and gradually decreases from the highest point of the outer circle to the middle of the outer circle, and the transition to the upper parting surface of the box is 0, and the length of the pad is made as a whole along the length of the casting 1;

[0035] c: the sand accumulation groove 3 is arranged along the length of the casting 1 at the top of the outer circle, and the sequential feeding is also strengthened;

[0036] d: a row of external chillers 5 is arranged along the length direction at the lower part of the outer circle of the casting 1, the width of the external chiller 5 is in the range of corresponding angle α = 40°-55° of the outer circle, and the thickness is equal to the wall thickness of the casting 1.

[0037] S4: design of the riser 4: the riser 4 is arranged at the uppermost of the outer circle of the casting 1, and the size and shape of the riser 4 are determined by using the modulus method according to M 冒 ≥1.2M 件 ;

[0038] Wherein, M 冒 =V 冒 / A 冒 , M 冒 is the modulus of the riser, V 冒 is the volume of the riser, A 冒 is the surface area of the riser; M 件 =V 件 / A 件 , M 件 is the modulus of the casting 1, V 件 is the volume of the casting 1, A 件 is the heat dissipation surface area of the casting 1;

[0039] The number of risers 4 is determined according to the feeding distance; the riser area = 4M 件 ; the end area = 5M 件 ;

[0040] The riser 4 is checked according to the feeding liquid amount method, η*G 冒 ≥(G 件 +G 冒 ) * ε check; G 冒 is the weight of the riser; G 件 is the weight of the casting of the feeding part of the riser; η is the feeding efficiency of the riser; ε is the volume shrinkage rate of the metal liquid.

[0041] S5: according to the design of S1-S4, sand box molding is adopted, the outer shape is divided into upper and lower boxes, the inner hole is made into an integral sand core, and the core head is taken out at both ends, and pouring is carried out after the box is closed.

[0042] Preferably, the surface sand layer thickness of the mold is set to 50-100 mm.

[0043] Preferably, the surface sand layer thickness around the gate is set to 100-150 mm.

[0044] Preferably, the space between the outer chill 5 and the mold is filled with chromite sand, and the sand layer thickness is 10-20 mm.

[0045] The parts of the present application not described in detail are the prior art.

[0046] The examples selected herein for the purpose of disclosing the inventive concept of the present application are presently considered to be the most practical and preferred, it being understood, however, that this application is intended to include all embodiments which come within the scope of the concept and the invention.

Claims

1. A casting process for a circular tubular cast steel part, characterized in that, The specific steps are as follows: S1: Based on the product structure of the round tube casting, a scheme of horizontal placement of the round tube casting for pouring is adopted, and the parting and mold separation are carried out at the horizontal center of the outer circle of the round tube casting. S2: The gating system adopts an open design with a cross-sectional ratio of sprue: sprue: runner: ingate = 1: (1.8-2.0): (1.8-2.0): (2.0-2.5); the ingate is located at the end of the casting and 60-100mm below the parting line. S3: Compensation Channel Design: a: The casting is fully machined, and the machining allowance is placed according to the standard. The center of the inner circle of the casting is offset downwards, and the offset value is half of the machining allowance, forming a feeding channel for sequential solidification with a thicker top and thinner bottom. b: Set a riser subsidy on the upper half of the outer circle of the casting. Starting from the highest point of the outer circle, add 2 / 3 of the outer circle machining allowance and gradually move downwards to the two ends of the upper box parting surface in the middle of the outer circle, transitioning to 0. The subsidy length is made as a whole with the length of the casting. c: Set a sand accumulation groove along the length of the casting at the top of the outer circle, which also strengthens the feeding sequence; d. A row of external chills is set along the length of the lower part of the outer circle of the casting. The width of the external chills is in the range of 40°-55° corresponding to the included angle α of the outer circle, and the thickness is 1-1.2 times the wall thickness of the casting. S4: Riser Design: The riser is placed at the top of the outer circle of the casting. The size and shape of the riser are determined using the modular method according to M. 冒 ≥1.2M 件 calculate; Among them, M 冒 =V 冒 / A 冒 M 冒 For riser modulus, V 冒 Let A be the riser volume. 冒 M is the surface area of ​​the riser; 件 =V 件 / A 件 M 件 V is the casting module. 件 For the volume of the casting, A 件 This refers to the heat dissipation surface area of ​​the casting; The number of risers is determined by the feeding distance; riser zone = 4M 件 End region = 5M 件 ; The riser check is performed using the replenishment volume method, η*G 冒 ≥(G 件 +G 冒 )*ε verification; G 冒 G is the weight of the riser. 件 η is the weight of the casting in the riser feeding section; η is the riser feeding efficiency; ε is the volume shrinkage rate of the molten metal. S5: Based on the design of S1 to S4, a sand box shape is adopted. The outer shape is divided into upper and lower boxes, and the inner hole is made into an integral sand core. The core head is produced at both ends, and the casting is done after the box is closed.

Images