CN-122013062-A - W-Mo-V hot work die steel and preparation method thereof

Abstract

The embodiment of the invention provides W-Mo-V hot work die steel and a preparation method thereof, wherein the W-Mo-V hot work die steel comprises, by weight, 0.45-0.65% of C, 0.2-0.5% of Si, 0.5-0.8% of Mn, 4.5-5.5% of Cr, 3.0-4.0% of Mo, 1.0-2.0% of W, 1.2-1.5% of V, 0.1-0.3% of Al and the balance of Fe. The high hardness (more than or equal to 55 HRC), high toughness (the impact absorption energy is more than or equal to 150J) and excellent high temperature performance (the hardness at 650 ℃ is more than or equal to 48 HRC) are realized by optimizing components (C, V, W, mo and the like) and the process (deep cooling and secondary tempering), and the method is suitable for manufacturing high-end hot working dies.

Inventors

• LIU PENG
• LIU HENG
• ZHOU YONGLI
• YANG ZHEN
• ZHANG PENG
• CHEN BIQIANG
• XIE BEIBEI
• XU PENGJIANG
• YUAN YONG
• YAN JINGBO
• ZHANG HUAN
• Huang Guanshuo
• Ding Kailun
• Fan Kaifa

Assignees

• 西安热工研究院有限公司
• 中国华能集团有限公司

Dates

Publication Date

20260512

Application Date

20260302

Claims (7)

1. 1. A W-Mo-V hot work die steel is characterized by comprising, by weight, 0.45-0.65% of C, 0.2-0.5% of Si, 0.5-0.8% of Mn, 4.5-5.5% of Cr, 3.0-4.0% of Mo, 1.0-2.0% of W, 1.2-1.5% of V, 0.1-0.3% of Al and the balance of Fe.
2. 2. The W-Mo-V hot work die steel according to claim 1, wherein the weight percentage content of C in the W-Mo-V hot work die steel is 0.6-0.65%.
3. 3. The W-Mo-V hot work die steel composition according to claim 1, wherein the weight percentage content of Cr of the W-Mo-V hot work die steel is 4.5%.
4. 4. A W-Mo-V hot work die steel composition according to any one of claims 1 to 3, characterized in that the weight percentage content of Mn in the W-Mo-V hot work die steel is 0.7-0.8%.
5. 5. A W-Mo-V hot work die steel according to any one of claims 1 to 3, wherein the sum of the w+mo weight percentage contents in the W-Mo-V hot work die steel is 5 to 6%.
6. 6. A W-Mo-V hot work die steel according to any one of claims 1 to 3, characterized in that the weight percentage content of V in the W-Mo-V hot work die steel is 1.5%.
7. 7. A method for producing a W-Mo-V hot work die steel according to any one of claims 1 to 6, characterized in that the method comprises the steps of: Step 1, raw materials are placed into a high-frequency vacuum induction smelting furnace according to a proportion, the heating temperature is 1450-1600 ℃, the vacuum degree is 0.5-0.6X10- -2 Pa, the raw materials are refined for 5-8min at 1550 ℃ after being melted completely, inert gas is then introduced, a crucible is cast into ingots to obtain refined ingots, the temperature is kept at 1200-1240 ℃ for 10-20h for homogenization treatment, the first step is forging on a forging machine after the heat treatment, the forging temperature is 1150-1200 ℃, the final forging temperature is more than or equal to 900 ℃, and the air cooling is carried out after the forging; Step 2, spheroidizing annealing, heat preservation for 2 hours at 850 ℃, slow cooling to 720 ℃, heat preservation for 4 hours at 720 ℃, furnace cooling to below 500 ℃ and discharging; step 3, quenching, namely preserving heat for 1h at 1050-1080 ℃ and oil quenching to room temperature; step 4, deep cooling treatment, namely deep cooling at-196 ℃ for 24 hours, so as to reduce residual austenite; and 5, tempering, namely preserving heat for 2 hours at 580-600 ℃, tempering twice, and air cooling.

Description

W-Mo-V hot work die steel and preparation method thereof Technical Field The embodiment of the invention relates to the technical field of hot work die steel, in particular to W-Mo-V hot work die steel and a preparation method thereof. Background The hot working die steel is mainly used for manufacturing special dies such as die-casting dies, forging dies and extrusion dies, and is often subjected to cyclic reciprocating impact load in the service process, and has higher impact performance for reducing the overall cracking risk and higher hardness for maintaining the dimensional accuracy under the high-temperature friction condition. The traditional hot working die steel is generally Cr-Mo-V martensitic alloy steel, and the die steel is favored because of excellent mechanical property proportion. However, cr-Mo-V hot work die steel also has its own performance short plate, the thermal conductivity is not high, which will limit the production efficiency of the product greatly. The traditional hot working die steel (such as H13 steel) is easy to have the problems of hardness reduction, insufficient toughness and the like at high temperature. In recent years, improvements in the performance of hot-work die steel by adding elements such as W, mo, V have become a research focus. In order to improve the service performance of H13 steel, students at home and abroad have conducted a great deal of researches on the aspects of optimizing design of alloy components, improving smelting process, improving forming technology, improving heat treatment process and the like. Alloy composition optimization is one of the most direct and effective ways to improve service performance such as high-temperature strength, and many scholars have conducted intensive studies on the alloy composition optimization. For example, by reducing the Cr content in H13 steel, the precipitation of Cr 23C6 carbide with low hardness and high coarsening rate is reduced, and the high-temperature strength and the tempering resistance stability can be obviously improved. In addition, the optimization of the heat treatment process can effectively improve the service performance such as high-temperature strength and the like. Therefore, on the basis of H13 steel, the problems of insufficient high-temperature strength above 600 ℃ of the conventional H13 steel are solved by reasonably adjusting Cr content, increasing Mo content, adding W element and improving trace V content and simultaneously assisting in a proper heat treatment process. However, in the prior art, W-Mo-V hot work die steel is easy to be coarsened by carbide during high-temperature tempering, so that the toughness is obviously reduced (such as HDLM steel), or the hardness is not improved enough (such as HBJ2 steel). The performance of the hot work die steel after quenching and tempering heat treatment is improved to a certain extent, but the phenomena of softening and insufficient strength still occur in some severe environments. The cryogenic process is a cold treatment process method for preserving heat of materials in a low-temperature environment by taking liquid nitrogen as a refrigerant, and the process has relatively low cost, high efficiency and no pollution. The prior researches show that the cryogenic process treatment can improve the uniformity and mechanical property of the steel structure and prolong the service life of the steel. Disclosure of Invention The embodiment of the invention aims at solving at least one of the technical problems existing in the prior art and provides W-Mo-V hot work die steel and a preparation method thereof. In a first aspect, the embodiment of the invention provides W-Mo-V hot work die steel, which comprises, by weight, 0.45-0.65% of C, 0.2-0.5% of Si, 0.5-0.8% of Mn, 4.5-5.5% of Cr, 3.0-4.0% of Mo, 1.0-2.0% of W, 1.2-1.5% of V, 0.1-0.3% of Al and the balance of Fe. Further, the weight percentage content of C in the W-Mo-V hot work die steel is 0.6-0.65%. Further, the weight percentage content of Cr of the W-Mo-V hot work die steel is 0.45%. Further, the weight percentage content of Mn in the W-Mo-V hot work die steel is 0.7-0.8%. Further, the sum of the weight percentage of W+Mo in the W-Mo-V hot work die steel is 5-6%. Further, the weight percentage content of V in the W-Mo-V hot work die steel is 1.5%. In a second aspect, an embodiment of the present invention provides a method for preparing a W-Mo-V hot work die steel according to the foregoing description, the method comprising the steps of: Step1, raw materials are placed into a high-frequency vacuum induction smelting furnace according to a proportion, the heating temperature is 1450-1600 ℃, the vacuum degree is 0.5-0.6X10- -2 Pa, the raw materials are refined for 5-8min at 1550 ℃ after being melted completely, inert gas is then introduced, a crucible is cast into ingots to obtain refined ingots, the temperature is kept at 1200-1240 ℃ for 10-20h for homogenization treatment, the first step