Economical long service life material for mechanical press forging die and manufacturing method thereof

Abstract

The invention provides an economic material with long service life used for a mechanical press forging die and a manufacture method thereof. The material comprises the following compositions by weight percentage: 0.42 to 0.46 percent of C, 0.20 to 0.40 percent of Si, 0.80 to 1.00 percent of Mn, 1.90 to 2.10 percent of Cr, 0.18 to 0.22 percent of V, 0.42 to 0.48 percent of Mo, 0.30 to 0.50 percent of Ni, less than or equal to 0.20 percent of Cu, 0.02 to 0.05 percent of Ti, 0.018 to 0.045 percent of Al, less than or equal to 0.012 percent of P, less than or equal to 0.013 percent of S, less than or equal to 0.0100 percent of N, and the balance being Fe. The method comprises the following steps: casting the compositions to a large steel ingot over 10 tons according to the proportion by electric furnace and external refine smelting; hot loading the steel ingot at a temperature more than or equal to 650 DEG C; heating a forge furnace at a heating speed of between 100 and 150 DEG C / hour to a temperature of between 1,220 and 1, 240 DEG to be insulated for over 5 hours; and forging the steel ingot into the dimension of a finished product by continuous upsetting and drawing out in one heat at a temperature of between 850 and 1,150 DEG C with ratio of forging reduction more than or equal to 5. Compared with the prior mechanical press forging die steel which is used most widely at home and abroad, the material has lower alloy element value, and improves the service life of the die almost by 1 time under the condition of using the same mechanical press forging die.

Description

technical field [0001] The invention belongs to the field of modules for thermal working dies, and in particular relates to a material for machine forging dies and a manufacturing method thereof. Background technique [0002] Hot work die steel can be generally divided into four types according to the application: hammer forging die steel, machine forging die steel, hot extrusion die steel, hot die casting die steel. Machine forging dies bear a large impact load during work; In the process, the mold cavity is in contact with the forging billet with a temperature of about 1000°C, and the temperature rise of the working surface of the mold often reaches 300-400°C, and sometimes it can reach 500-600°C locally; therefore, it is required that the mold can have A certain amount of toughness. [0003] At present, the most widely used machine forging die steel at home and abroad is 5CrNiMo, and its standard composition range is: C0.50~0.60wt%, Si≤0.40wt%, Mn 0.50~0.80wt%, P≤0.030wt...

AI Technical Summary

Problems solved by technology

[0006] 1) After the steel ingot is annealed, the forging heating time is long, the energy consumption is high, and the manufacturing cost is high

[0007] 2) Compared with large steel ingot forging, the output per unit time of small steel ingot forging is low, which reduces the production capacity of fast forging machine and increases the manufacturing cost

[0008] 3) The forged material adopts 2 fires to form a material, the first fire is upsetting, and after returning to the furnace for reheating, the second fire is drawn to the finished product specification, and the product manufacturing cost is high

[0010] Chinese patent application number CN200610038628.6 discloses "a high wear-resistant hot forging die cast steel". Low problem

[0013] Chinese Patent Application No. CN02133244.4 "New Casting Hot Forging Die Steel" is to solve the shortcomings of high manufacturing cost, low material utilization rate and large waste of resources in the current hot forging die manufacturing technology, and realize "casting instead of forging" , improve the thermal mechanical fatigue resistance, wear resistance and plastic deformation resistance of cast hot forging die steel, improve its service life and reduce its manufacturing cost

[0015] From the perspective of manufacturing process: the first and fourth patents adopt casting molding process, which can improve the utilization rate of materials, but the steel retains casting defects, which affects the performance of the mold

[0016] To sum up, in the currently known public technology and patent literature, the steel for machine forging dies with an alloy content of about 3% is usually 5CrNiMo, but the thermal stability is poor, and the hardness of the die will increase due to the use of temperature in continuous production. failure due to drop

The optimized machine forging die material uses tungsten as an important alloy element to improve high-temperature strength, and the alloy content is controlled at ≥5%, or even ≥8%, and the production cost is relatively high

Therefore, some patented technologies use casting molding technology to improve material utilization and reduce waste, but there are casting defects in the material, which affects the service life

However, economical long-life machine forging die steel with low alloy content and good thermal stability has no relevant patent publications.

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