Forging method for improving yield of free-cutting steel die ingot forging

Abstract

The invention relates to a forging method for improving the yield of free-cutting steel die cast ingot forgings, which is mainly implemented as follows: during forging of an oil press, an upper flat anvil and a lower V anvil are adopted to ensure the synchronism of axial flow of die cast ingot metal, and then a pulling forging mode is adopted at the end part of an upper riser of a radial forging machine; and finally, a step is reserved at the end part of the riser, and the end part of the riser attached with the casting powder extends out of the forge piece body in a two-time pulling and forging manner, so that the utilization rate of the forge piece is finally improved.

Description

Technical Field

[0001] The invention belongs to the field of forging free-cutting steel, and in particular relates to a forging method for improving the yield rate of free-cutting steel die casting ingot forgings. Background Art

[0002] Free-cutting steel has higher cutting performance and good mechanical properties than carbon steel. When machining parts with free-cutting steel, it is easy to break chips, extend tool life, shorten machining time, and thus reduce production costs. Free-cutting steel is mainly produced by adding appropriate amounts of sulfur, calcium and other elements to the steel. Therefore, this type of steel has the characteristics of high viscosity of molten steel, resulting in impurities such as protective slag attached to the riser end. Conventional forging methods have insufficient control over such defects, which can easily lead to defects extending into the forging body, thereby reducing the yield rate of die casting ingots and increasing production costs. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of conventional forging technology and to propose a forging method that can avoid the extension of the riser line of the steel ingot to the forging, thereby improving the yield rate of free-cutting steel die cast ingot forgings. Compared with conventional forging methods, this forging method can improve the yield rate of die cast ingots by more than 3%.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows: A forging method for improving the yield rate of free-cutting steel die ingot forgings, the method comprising the following steps: Step 1), after demoulding, the die-cast ingot is transferred to the forging workshop, and after heating, it is forged into φ450-φ500mm billets on a 3150-ton hydraulic press. The upper flat anvil and the lower V anvil are used in the forging process; Step 2), the blank of step 1) is transferred to the radial forging machine for forging, the ingot tail is pointed to the B chuck, the deformation is 60-70mm, the B side is pulled and beaten, the pulling speed is 4-5m / min, and the empty pass is returned after the forging is completed; Step 3), the billet of step 2) is directed to the B chuck with the ingot tail pointing, the deformation is 70-80mm, the B side is pulled and beaten, the pulling speed is 6-7m / min, and the empty pass is returned after the forging is completed; Step 4), the billet of step 3) is directed to the B chuck with the ingot tail pointed, the deformation is 30-40mm, the pulling speed is 4-5m / min, and the pulling is stopped when the distance from the riser end is 400-600mm. After the billet rotates one circle, the empty pass returns; Step 5), forge the billet in step 4) to the finished product size, use B-side pulling, deformation 30~50mm, pulling speed 2-3m / min, stop pulling when forging to the billet step in step 4), after the billet rotates one circle, lift the hammer to forge the remaining billet to the finished product size in two passes.

[0005] In step 2), after the billet is transferred to the radial forging machine for forging, it is heated and kept warm during forging and then stretched by a 3150-ton hydraulic press on the 600mm upper and lower flat anvils for one pass. The reduction is controlled between 20% and 25%, ensuring that at least 20% of the overlap is ensured between every two anvils.

[0006] The present invention has the following beneficial effects: The technical solution of the present invention ensures the synchronization of the axial flow of the die-cast ingot metal by adopting an upper flat and lower V-anvil on the hydraulic press, and then adopts a pulling and beating forging method on the riser end of the radial forging machine to ensure that the riser end part of the attached protective slag does not extend toward the forging body, and finally, a step is reserved at the riser end, and the riser end part of the attached protective slag is extended outside the forging body by two pulling and beating forging methods, thereby finally improving the utilization rate of the forging. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a schematic diagram of the mold casting ingot in Example 1 of the present invention.

[0008] Figure 2 This is a schematic diagram of the blank in step 1) of Example 1 of the present invention.

[0009] Figure 3 This is a schematic diagram of the blank in step 2) of Example 1 of the present invention.

[0010] Figure 4 This is a schematic diagram of the blank in step 3) of Example 1 of the present invention.

[0011] Figure 5 This is a schematic diagram of the blank in step 4) of Example 1 of the present invention.

[0012] Figure 6 This is a schematic diagram of the finished product in step 5) in Example 1 of the present invention. DETAILED DESCRIPTION

[0013] The present invention will be further described and illustrated below in conjunction with specific embodiments.

[0014] Example 1: Steel grade: ASTM 1141; Ingot weight: 5000 kg; Forging specification: φ260 mm.

[0015] The smelting process uses a 40-ton electric furnace smelting combined with a 40-ton vacuum refining furnace, and the forging process uses a 3150-ton hydraulic press combined with a 1800-ton radial forging machine. The specific steps are as follows: Step 1), 5 tons of die casting ingot is forged into a billet of φ480 using upper flat anvil and lower V anvil on a 3150 tons hydraulic press; Step 2), the billet of step 1) is transferred to a 1800-ton radial forging machine, and the billet is forged to φ415 using an R180 hammer, with the tail of the ingot pointing to the B chuck, and the B side is pulled and beaten at a speed of 4-5m / min. After forging, the empty pass is returned; Step 3), the billet of step 2) is forged into a billet of φ340 using an R180 hammer on a 1800-ton radial forging machine, with the tail of the ingot pointing to the B chuck, and the B side is pulled and beaten at a speed of 6-7m / min. After forging, the empty pass is returned; Step 4), the billet of step 3) is forged into a φ305 billet using an R180 hammer on a 1800-ton radial forging machine, wherein the billet riser end is 400-600 mm long and is not forged, the ingot tail points to the B chuck, and the B side is pulled and beaten at a speed of 4-5 m / min. When the distance from the riser end is 500 mm, the pulling and beating is stopped, and the billet is returned after rotating one circle in an empty pass; Step 5), forge the billet with a step at the riser end of step 4) to a finished size of φ260 using an R180 hammer on an 1800-ton radial forging machine, with the ingot tail pointing to the B chuck, and use B-side pulling and beating at a speed of 2-3m / min. Stop pulling and beating when the billet is at the step in step 4), that is, 500mm long from the riser end. After the billet rotates one circle, lift the hammer and forge the remaining 500mm long billet in two passes to the finished size.

[0016] Forgings produced according to the above method are inspected after subsequent annealing. The surface quality of the forgings is good. The utilization rate of the forgings is shown in the following table: Production plan Specification Utilization Conventional forging method Φ300 78% Forging method of the present invention Φ300 82.5% Conventional forging method Φ260 79% Forging method of the present invention Φ260 83% .

Claims

1. A forging method for improving the yield rate of free-cutting steel die ingot forgings, characterized in that: The method comprises the following steps: Step 1), after demoulding, the die-cast ingot is transferred to the forging workshop, and after heating, it is forged into φ450-φ500mm billets on a 3150-ton hydraulic press. The upper flat anvil and the lower V anvil are used in the forging process; Step 2), the blank of step 1) is transferred to the radial forging machine for forging, the ingot tail is pointed to the B chuck, the deformation is 60-70mm, the B side is pulled and beaten, the pulling speed is 4-5m / min, and the empty pass is returned after the forging is completed; Step 3), the billet of step 2) is directed to the B chuck with the ingot tail pointing, the deformation is 70-80mm, the B side is pulled and beaten, the pulling speed is 6-7m / min, and the empty pass is returned after the forging is completed; Step 4), the billet of step 3) is directed to the B chuck with the ingot tail pointed, the deformation is 30-40mm, the pulling speed is 4-5m / min, and the pulling is stopped when the distance from the riser end is 400-600mm. After the billet rotates one circle, the empty pass returns; Step 5), forge the billet in step 4) to the finished product size, use B-side pulling, deformation 30~50mm, pulling speed 2-3m / min, stop pulling when forging to the billet step in step 4), after the billet rotates one circle, lift the hammer to forge the remaining billet to the finished product size in two passes.

2. A forging method for improving the yield rate of free-cutting steel die ingot forgings according to claim 1, characterized in that: In step 2), after the billet is transferred to the radial forging machine for forging, it is heated and kept warm during forging and then stretched by a 3150-ton hydraulic press on the 600mm upper and lower flat anvils for one pass. The reduction is controlled between 20% and 25%, ensuring that at least 20% of the overlap is ensured between every two anvils.

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