CN106862442A - A kind of casting without material head shaft forgings-roll manufacturing process - Google Patents

Abstract

The invention discloses a casting-rolling forming method for a headless shaft, which is characterized in that a casting mold is made, the casting mold is embedded in a sand mold box to form a mold, and gates and risers are arranged in the sand mold box. Open the sprue groove, pierce the air holes, then inject the molten steel into the casting mold, and cool it after pouring until the core temperature of the casting is 1100°C-1200°C and the surface temperature is 750°C-800°C, then shake out, take out two Finally, the cast bar is immediately rolled on the cross wedge rolling mill, and rolled under the condition of controlling the area reduction rate of the rolled piece to be 75% to 95% to obtain the headless shaft. The advantage is that due to the combination of casting and cross-wedge rolling to process shafts, the casting bars can better avoid the generation of concave centers at the ends during cross-wedge rolling, and further improve the quality of the product. The material utilization rate is high, and the quality of the rolled piece is good.

Description

A casting-rolling forming method for a headless shaft

technical field

The invention relates to the processing of shafts, in particular to a casting-rolling forming method for shafts without material heads.

Background technique

Cross wedge rolling is a new process for forming shafts, which has the characteristics of high production efficiency. However, since the rolling process of cross wedge rolling is a deformation process of metal radial compression and axial extension, the surface metal flows faster than the core metal when rolling the shaft, which causes a larger concave center at the end, resulting in Roll-formed shaft parts produce splinters, which need to be removed by setting a cutter on the mold, which reduces the utilization rate of materials to a certain extent. In order to avoid the material head of the shaft parts, some people heat the bar first, and then process the end into a tapered shape, but this requires auxiliary equipment to pre-cut the end, and the effect of eliminating the concave center of the shaft end is not too great. it is good. In addition, the current bars need to be heated twice or three times before cross wedge rolling, which consumes a lot of power and cannot meet the needs of energy saving and emission reduction.

Contents of the invention

The technical problem to be solved by the present invention is to provide a casting-rolling forming method for headless shafts with high material utilization rate, good product quality, energy saving and consumption reduction.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a method for casting-rolling forming of shafts without material head, including the following specific steps:

(1) Make a casting mold with both ends in the shape of a truncated cone and an inner diameter of 30-200mm;

(2) Embed the casting mold in the sand mold box, fill and compact the surrounding of the casting mold with molding sand, and then fill with resin sand to form a mold;

(3) Set gates and risers in the sand box, open sprue grooves, and pierce air holes;

(4) Pour the molten steel into the casting mold. The pouring temperature of the molten steel is 1300°C-1500°C, and the pouring time is 20-25s. After pouring, it is cooled until the core temperature of the casting is 1100°C-1200°C and the surface temperature is 750 ℃ ~ 800 ℃, then shake out the sand, take out the casting bar with both ends of the truncated cone and a diameter of 30 ~ 200mm;

(5) Immediately put the casting bars on the cross wedge rolling mill for rolling, and roll them under the condition that the reduction of area of the rolled parts is controlled at 75% to 95% to obtain shafts without heads.

Compared with prior art, the advantage of the present invention is:

(1) Due to the method of combining casting and cross wedge rolling to process shaft parts, by controlling the temperature gradient of the casting bar from the center to the surface during casting, and casting the two ends of the casting bar into a truncated cone shape, so that When the casting bar is rolled by cross wedge rolling, it can better avoid the generation of concave center at the end, which further improves the material utilization rate of the product, and the material utilization rate can reach more than 98%.

(2) During cross-wedge rolling, the reduction of area of the rolled piece is controlled to 75% to 95%. Rolling under the condition of large reduction of area in cross-wedge rolling can break the dendrites of the casting, making the grains finer, and obtaining High quality rolled parts.

(3) Through direct casting of molten steel and direct rolling of casting bars with residual temperature to obtain shaft parts, the process flow of shaft part forming is reduced, the production efficiency of shaft parts is improved, and the production efficiency of shaft parts is avoided. Secondary heating to achieve the purpose of saving energy and reducing consumption.

detailed description

Below in conjunction with embodiment the present invention is described in further detail.

Embodiment 1: A casting-rolling forming method of a headless shaft, comprising the following specific steps:

(1) Make a casting mold with both ends in the shape of a truncated cone and an inner diameter of 50mm;

(2) Embed the casting mold in the sand mold box, fill and compact the surrounding of the casting mold with molding sand, and then fill with resin sand to form a mold;

(3) Set gates and risers in the sand box, open sprue grooves, and pierce air holes;

(4) Pour 45# molten steel into the casting mold. The pouring temperature of the molten steel is 1400°C, and the pouring time is 20s. After pouring, it is cooled until the core temperature of the casting is 1100°C and the surface temperature is 800°C. Shake out sand then, take out the casting bar stock that both ends are conical shape, and diameter is 50mm;

(5) Immediately put the casting bar stock on the cross wedge rolling mill for rolling, and roll it under the condition of controlling the reduction of area of the rolled piece to 75% to obtain a headless shaft piece made of 45# steel.

Embodiment 2: A casting-rolling forming method for a shaft without a head, comprising the following specific steps:

(1) Make a casting mold with both ends in the shape of a truncated cone and an inner diameter of 100mm;

(2) Embed the casting mold in the sand mold box, fill and compact the surrounding of the casting mold with molding sand, and then fill with resin sand to form a mold;

(3) Set gates and risers in the sand box, open sprue grooves, and pierce air holes;

(4) Pour molten steel made of 42CrMo into the casting mold. The pouring temperature of the molten steel is 1500°C, and the pouring time is 25s. After pouring, it is cooled until the core temperature of the casting is 1200°C and the surface temperature is 800°C. Then Shakeout, take out the casting bars whose both ends are frustum-shaped and have a diameter of 100mm;

(5) Immediately put the casting bar on the cross wedge rolling mill for rolling, and roll it under the condition of controlling the reduction of area of the rolled piece to 80% to obtain a 42CrMo headless shaft.

Embodiment 3: A casting-rolling forming method for a shaft without a material head, comprising the following specific steps:

(1) Make a casting mold with both ends in the shape of a truncated cone and an inner diameter of 200mm;

(2) Embed the casting mold in the sand mold box, fill and compact the surrounding of the casting mold with molding sand, and then fill with resin sand to form a mold;

(3) Set gates and risers in the sand box, open sprue grooves, and pierce air holes;

(4) Pour 40Cr molten steel into the casting mold. The pouring temperature of the molten steel is 1300°C, and the pouring time is 23s. After pouring, it is cooled until the core temperature of the casting is 1200°C and the surface temperature is 750°C. Then Shakeout, take out a casting bar with both ends of a truncated cone and a diameter of 200mm;

(5) Immediately put the casting bar on the cross wedge rolling mill for rolling, and roll it under the condition of controlling the reduction of area of the rolled piece to 90% to obtain a 40Cr headless shaft.

In addition, the above method is also applicable to the processing of headless shafts made of other non-ferrous metals.

Claims (1)

1. A casting-rolling forming method of a headless shaft, characterized in that it comprises the following specific steps: (1) Make a casting mold with both ends in the shape of a truncated cone and an inner diameter of 30-200mm; (2) Embed the casting mold in the sand mold box, fill and compact the surrounding of the casting mold with molding sand, and then fill with resin sand to form a mold; (3) Set gates and risers in the sand box, open sprue grooves, and pierce air holes; (4) Pour the molten steel into the casting mold. The pouring temperature of the molten steel is 1300°C-1500°C, and the pouring time is 20-25s. After pouring, it is cooled until the core temperature of the casting is 1100°C-1200°C and the surface temperature is 750 ℃ ~ 800 ℃, then shake out the sand, take out the casting bar with both ends of the truncated cone and a diameter of 30 ~ 200mm; (5) Immediately put the casting bars on the cross wedge rolling mill for rolling, and roll them under the condition that the reduction of area of the rolled parts is controlled at 75% to 95% to obtain shafts without heads.