CN-121976006-A - Method for improving hardness uniformity of die casting machine module forging

CN121976006ACN 121976006 ACN121976006 ACN 121976006ACN-121976006-A

Abstract

The invention belongs to the technical field of heat treatment of forgings, and discloses a method for improving hardness uniformity of a die casting machine module forgings, which comprises the steps of controlling carbon content of the die casting machine module forgings to be 0.32-0.35% and controlling carbon equivalent [ C ] to be not more than 0.60%, heating to 340-360 ℃, preserving heat for 180+/-10 min, heating to 640-660 ℃, preserving heat for 300+/-10 min, heating to 860-880 ℃, preserving heat for 1080+/-10 min, air-cooling for 1.5-2.5 min, water-cooling according to 15-18 min/100mm, air-cooling, heating to 340-360 ℃, preserving heat for 180+/-10 min, heating to 550-570 ℃, preserving heat for 2400+/-10 min, and cooling in a furnace to room temperature. The method ensures that the full-section hardness of the die casting machine module forging is within the range of 30-34 HRC and the hardness difference is smaller than 4HRC.

Inventors

LIANG XIAOJIE
LIU ZHILONG
LIANG GUOPING
GAO CHAOPING
WU XINGGE
WANG YIPING
WANG XUYING
ZHANG YUN
HU YUNBAO

Assignees

太原重工股份有限公司

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (5)

1. A method of improving hardness uniformity of a die casting machine module forging, comprising: (1) Forging material composition internal control The chemical components of the die casting machine module forging piece are controlled to be 0.32-0.35% by weight of C, 0.25-0.5% by weight of Si, 0.6-0.8% by weight of Mn, 1.4-1.7% by weight of Cr, 0.30-0.45% by weight of Mo, 0.015-0.030% by weight of Al, and the balance of Fe and unavoidable impurity elements; (2) Optimization of heat treatment process Carrying out performance heat treatment on the die casting machine module forging, wherein the heat treatment process is optimized as follows: Heating a die casting machine module forging to 340-360 ℃, preserving heat for 180+/-10 min, then heating to 640-660 ℃, preserving heat for 300+/-10 min, then heating to 860-880 ℃, and preserving heat for 1080+/-10 min; Air cooling for 1.5-2.5 min after heat preservation is finished, then water cooling is carried out according to the thickness of the die casting machine module forging piece and 15-18 min/100mm, and air cooling is carried out after water cooling is finished; And tempering the die casting machine module forging for one time, heating the die casting machine module forging to 340-360 ℃, preserving heat for 180+/-10 min, heating to 550-570 ℃, preserving heat for 2400+/-10 min, and cooling in a furnace to room temperature.
2. The method for improving the hardness uniformity of a die casting machine module forging according to claim 1, wherein the chemical composition of the die casting machine module forging is internally controlled to be material carbon equivalent [ C ] < 0.60%, wherein: ; In the formula, The carbon equivalent of the die casting machine module forging steel, 、、 The weight percentage content of C, mn, cr, mo in the die casting machine module forging steel is respectively.
3. The method for improving the hardness uniformity of a die casting machine module forging according to claim 1, wherein the heat treatment process is optimized as follows: heating the die casting machine module forging to 350 ℃ at a heating rate of 60-90 ℃ per hour, preserving heat for 180min, heating to 650 ℃ at a heating rate of less than or equal to 40 ℃ per hour, preserving heat for 300min, heating to 870 ℃ at a heating rate of less than or equal to 70 ℃ per hour, and preserving heat for 1080min; air cooling for 2min after heat preservation is finished, then water cooling is carried out according to the thickness of the die casting machine module forging piece and 17min/100mm, and air cooling is carried out after water cooling is finished; And tempering the die-casting machine module forging for one time, heating the die-casting machine module forging to 350 ℃ at a temperature rising speed of 60-90 ℃ per hour, heating to 560 ℃ at a temperature rising speed of less than or equal to 40 ℃ per hour after heat preservation for 180min, and cooling to room temperature in a furnace at a temperature reducing speed of 80 ℃ per hour after heat preservation for 2400 min.
4. The method for improving the hardness uniformity of a die casting machine module forging according to claim 1, wherein when the die casting machine module forging is subjected to heat treatment, the die casting machine module forging is placed in a heating furnace in a side-stand state, and a 70mm thick steel plate is used for supporting the bottom.
5. The method for improving the uniformity of hardness of a die casting machine module forging according to any one of claims 1 to 4, wherein the die casting machine module forging has a full-section hardness in a range of 30-34 HRC and a hardness difference of less than 4HRC.

Description

Method for improving hardness uniformity of die casting machine module forging Technical Field The invention belongs to the technical field of heat treatment of forgings, and particularly relates to a method for improving hardness uniformity of a die casting machine module forgings. Background The integrated die casting technology is one of important technical routes for realizing light weight, and a plurality of parts which are required to be assembled originally are designed to be die-cast and molded once through an integrated die casting die by a die casting machine, so that a complete integrated die casting die frame is directly obtained. The die casting machine module forging piece is a key part required by the die casting machine integrated die casting mold. As schematically shown in fig. 1, the length and width of a die casting machine module forging are both over 3 meters, the thickness can reach over 1 meter at maximum, the weight of a single product before heat treatment is up to 70 tons, the problems of segregation of long and wide section components and uneven heating and cooling are unavoidable, and the hardness difference is large. The traditional manufacturing process is required to achieve the full-section hardness required by the die casting machine module forging within the range of 30-34 HRC, the hardness difference is not more than 4HRC, and the manufacturing difficulty is extremely high. Particularly, with the gradual enlargement of die casting machine module forging products, the heat treatment after forging and the performance heat treatment time exceed 280 hours, the equipment occupation problem is outstanding, the working efficiency is low, moreover, the traditional oil cooling method is adopted, and the uneven cooling speed of the core part and the surface easily causes overlarge tissue stress due to the size effect, so that the products are cracked. Therefore, there is a need to develop a method capable of improving the component uniformity and hardness uniformity of the die casting machine module forging product, so as to control the total section hardness of the product within the required range of 30-34 HRC and control the hardness difference within the range of 4HRC. Disclosure of Invention In order to solve some or all of the technical problems in the prior art, the invention provides a method for improving hardness uniformity of a die casting machine module forging, which comprises the following steps: (1) Forging material composition internal control The chemical components of the die casting machine module forging piece are controlled to be 0.32-0.35% by weight of C, 0.25-0.5% by weight of Si, 0.6-0.8% by weight of Mn, 1.4-1.7% by weight of Cr, 0.30-0.45% by weight of Mo, 0.015-0.030% by weight of Al, and the balance of Fe and unavoidable impurity elements; (2) Optimization of heat treatment process Carrying out performance heat treatment on the die casting machine module forging, wherein the heat treatment process is optimized as follows: Heating a die casting machine module forging to 340-360 ℃, preserving heat for 180+/-10 min, then heating to 640-660 ℃, preserving heat for 300+/-10 min, then heating to 860-880 ℃, and preserving heat for 1080+/-10 min; Air cooling for 1.5-2.5 min after heat preservation is finished, then water cooling is carried out according to the thickness of the die casting machine module forging piece and 15-18 min/100mm, and air cooling is carried out after water cooling is finished; And tempering the die casting machine module forging for one time, heating the die casting machine module forging to 340-360 ℃, preserving heat for 180+/-10 min, heating to 550-570 ℃, preserving heat for 2400+/-10 min, and cooling in a furnace to room temperature. Further, in the method for improving the hardness uniformity of the die casting machine module forging, the chemical composition of the die casting machine module forging is internally controlled to be the material carbon equivalent [ C ] < 0.60%, wherein: ; In the formula, The carbon equivalent of the die casting machine module forging steel,、、The weight percentage content of C, mn, cr, mo in the die casting machine module forging steel is respectively. Further, in the method for improving the hardness uniformity of the die casting machine module forging, the heat treatment process is optimized as follows: heating the die casting machine module forging to 350 ℃ at a heating rate of 60-90 ℃ per hour, preserving heat for 180min, heating to 650 ℃ at a heating rate of less than or equal to 40 ℃ per hour, preserving heat for 300min, heating to 870 ℃ at a heating rate of less than or equal to 70 ℃ per hour, and preserving heat for 1080min; air cooling for 2min after heat preservation is finished, then water cooling is carried out according to the thickness of the die casting machine module forging piece and 17min/100mm, and air cooling is carried out after water cooling is finished; And tempering the die-casting