A process for forging round steel of ultra-fine chromium molybdenum series hot work die steel

A hot work die steel, ultra-fine technology, applied in the field of hot work die steel forging, to achieve uniform microstructure, improve impact performance, and improve purity

Active Publication Date: 2021-10-19
东莞市正一金属制品有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the size of chromium-molybdenum series hot work die steel forged round steel in the domestic and foreign die steel market has increased to Ф600mm~Ф800mm. With the increase of forged round steel size, only larger steel ingots and more Large forging and pressing ratio

Method used

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  • A process for forging round steel of ultra-fine chromium molybdenum series hot work die steel
  • A process for forging round steel of ultra-fine chromium molybdenum series hot work die steel
  • A process for forging round steel of ultra-fine chromium molybdenum series hot work die steel

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The size and shape of the finished product is round steel Ф635mm.

[0039] ⑴ EAF+LF+VD+ESR method is used for smelting, LF furnace adopts white slag for 32 minutes; VD vacuum degree is not more than 0.67mbar, keep it for 10 minutes, pour φ700mm round electrode rod, pouring temperature is 1537 ℃, electrode rod is red and annealed. Binary slag-based CaF is used in electroslag remelting 2 :Al 2 o 3=70:30, the remelting voltage of constant melting rate electroslag furnace is controlled at 62V~74V, the remelting current is controlled at 15000A~20000A, the remelting melting speed is controlled at 13.5kg / min, and the electroslag remelting ingot type is φ1100mm electroslag Ingots, electroslag ingots are warmly sent to the next process. The chemical composition analysis results of electroslag ingots are shown in Table 1.

[0040] Table 1 Chemical composition analysis results

[0041]

[0042] (2) High-temperature diffusion treatment is carried out before forging φ1100mm ...

Embodiment 2

[0053] The size and shape of the finished product is round steel Ф685mm.

[0054] ⑴ EAF+LF+VD+ESR method is used for smelting, the LF furnace uses white slag for 31 minutes; the VD vacuum degree is not greater than 0.67mbar, keep it for 10 minutes, pouring φ700mm round electrode rods, the pouring temperature is 1541 ℃, and the electrode rods are red and annealed. Binary slag-based CaF is used in electroslag remelting 2 :Al 2 o 3 =70:30, the remelting voltage of constant melting rate electroslag furnace is controlled at 62V~74V, the remelting current is controlled at 15000A~20000A, the remelting melting speed is controlled at 13.5kg / min, and the electroslag remelting ingot type is φ1100mm electroslag Ingots, electroslag ingots are warmly sent to the next process. The chemical composition analysis results of electroslag ingots are shown in Table 4.

[0055] Table 4 chemical composition analysis results

[0056]

[0057] (2) High-temperature diffusion treatment is carried...

Embodiment 3

[0068] The size and shape of the finished product is round steel Ф785mm.

[0069] ⑴ EAF+LF+VD+ESR method is used for smelting, LF furnace adopts white slag for 34 minutes; VD vacuum degree is not more than 0.67mbar, keep it for 10 minutes, pour φ700mm round electrode rod, pouring temperature is 1533 ℃, electrode rod is red and sent for annealing. Binary slag-based CaF is used in electroslag remelting 2 :Al 2 o 3 =70:30, the remelting voltage of constant melting rate electroslag furnace is controlled at 62V~74V, the remelting current is controlled at 15000A~20000A, the remelting melting speed is controlled at 13.5kg / min, and the electroslag remelting ingot type is φ1100mm electroslag Ingots, electroslag ingots are warmly sent to the next process. The chemical composition analysis results of electroslag ingots are shown in Table 7.

[0070] Table 7 Chemical composition analysis results

[0071]

[0072] (2) High-temperature diffusion treatment is carried out before forgi...

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Abstract

The invention discloses a process for forging round steel of ultra-fine chromium-molybdenum series hot work die steel. The purpose is to solve the problem that the core structure and impact toughness of large forged round steel meet the technical requirements by adopting a special ultra-fine control technology. The invention adopts the LF furnace white slag method and the VD degassing steelmaking process to improve the purity of molten steel; it controls the electroslag remelting melting rate and the diffusion homogenization treatment before forging, and improves the as-cast structure segregation of large steel ingots and the heat dissipation of steel. Processing plasticity; and through the three-dimensional forging method of multi-firing and multi-direction for large-scale electroslag ingots, the carbides are broken and the microstructure uniformity of the core is improved; the finished material is heat-treated and forged, and the waste heat is directly used for direct water-air alternate quenching and isothermal Spheroidizing annealing uniformly refines the steel microstructure. The Ф600mm~Ф800mm ultra-fine chromium-molybdenum series hot work die steel forged round steel has reached the high-quality technical level of NADCA#207 standard.

Description

technical field [0001] The invention belongs to the field of hot work die steel forging, and in particular relates to a process for forging round steel of superfine chromium-molybdenum series hot work die steel. The diameter of the round steel is Ф600 mm to Ф800 mm. Background technique [0002] Die steel is a special alloy steel. Commonly used die steels are generally divided into three categories according to their use and working conditions, namely cold work die steel, hot work die steel and plastic die steel. Hot work die steel is mainly used to manufacture dies for hot forming of metals in high temperature state, such as hot forging dies, hot extrusion dies, etc. The carbon content of this type of steel is generally 0.3% to 0.6%, adding alloying elements such as tungsten, molybdenum, chromium, vanadium to improve performance, and can be divided into chromium molybdenum hot work die steel 4Cr5MoSiV1, etc., chromium tungsten hot work die steel 3Cr2W8V, 5Cr4W5Mo2V, etc. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/22C22C38/24B21J5/00C21D1/18C21D1/32C21D8/00C22B9/18C22C33/04
CPCB21J5/002C21D1/18C21D1/32C21D8/005C22B9/18C22C33/04C22C38/02C22C38/04C22C38/22C22C38/24
Inventor 林国忠
Owner 东莞市正一金属制品有限公司
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