Per-hardened plastic mould steel

A technology for plastic molds and mold steels, applied in the field of metal materials, can solve the problems of uneven hardness, poor hardenability of large cross-section materials, and poor purity, and achieve the effect of improving polishing performance, improving hardenability, and improving finish.

Active Publication Date: 2014-08-06
胡财基
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During thermal processing and heat treatment, Fe3C, Cr23C6, and Cr7C3 carbides are solid-dissolved into the matrix one after another, and the pinning effect cannot be achieved. Although M2C→M6C+MC has a certain pinning effect, a small amount cannot prevent the appearance of pre-hardened mold steel. Coarse flaky ferrite, sorbite and grain coarsening lead to quality problems such as poor hardenability and uneven hardness of large cross-section materials
In addition, the purity of 3Cr2MnMo (P20) large cross-section material becomes poor, usually A, B, C, D coarse and fine inclusions fluctuate in the range of 1.0~2.5, resulting in unstable polishing performance, and the surface finish of the mold fluctuates. Low
In summary, the above factors hinder the application and development of the steel

Method used

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  • Per-hardened plastic mould steel
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  • Per-hardened plastic mould steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The mass percentage of the plastic mold steel 3Cr2MnMo after the alloy phase improvement includes the following composition:

[0032] C: 0.35%;

[0033] Si: 0.55%;

[0034] Mn: 1.52%;

[0035] P: ≤0.008%;

[0036] S: ≤0.0004%;

[0037] Cr: 1.98%;

[0038] Mo: 0.45%;

[0039] Ni: 0.23%;

[0040] Nb: 0.08%;

[0041] Cu: ≤0.11%;

[0042] N: 0.004% (40PPM)

[0043] Fe:: margin.

[0044] The smelting process is as follows:

[0045] Converter provides low-phosphorus and low-sulfur molten steel→EAF deoxidation, degassing and inclusion removal→LF furnace refining→VD vacuum refining——→betting ingot / ESR ingot

[0046] Multi-directional deformation process (process): including the combination of radial and axial forging deformation of die steel and transverse and longitudinal multi-directional deformation.

[0047] Refined treatment process (process): Starting from the temperature of the die steel with the thickness of the finished product after forging, heat it to 880...

example 1

[0049] Example 1 The mechanical impact toughness test results of die steel 3Cr2MnMo before and after improvement are shown in Table 1:

[0050] Table 1

[0051]

[0052] The isotropy of 3Cr2MnMo after the reform is 0.92, and the isotropy of 3Cr2MnMo before the reform is 0.53, compared with an increase of 0.32.

example 2

[0053] Example 2 Die steel 3Cr2MnMo reform before and after polishing performance test results (in terms of polishing roughness),

[0054] Table 2

[0055]

[0056] The roughness of the 3Cr2MnMo polishing material before the reform is much higher than that of the 3Cr2MnMo after the reform, that is, the roughness changes from 0.5 μm to 0.3 μm.

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PUM

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Abstract

The invention discloses pre-hardened plastic mould steel. According to the 3Cr2MnMo mould steel, Mn is regulated to 1.30%-1.60% from 0.60%-1.00%, Ni is 0.10%-0.30%, and 0.05%-0.10% of trace nucleating agent element Nb is added; in mould steel, P is strictly controlled to be not greater than 0.015% and S is strictly controlled to be not greater than 0.003%; and the mould steel is refined and pre-hardened after being deformed in a poly-directional manner. According to the mould steel 3Cr2MnMo disclosed by the invention, due to alloying regulation in a steel cast structure, hardenability of the steel is improved, and the steel has good comprehensive performances such as good bending strength, compressive strength, impact toughness, and the like. By strictly controlling P and S harmful elements, purity and polishing performances of steel are improved. By adopting poly-directional deformation and refined microscopic structure, isophase performance of the steel is improved; and by adopting a refining and pre-hardening thermal treatment process, microscopic structure of the steel is further refined to form a uniform and small sorbite structure.

Description

technical field [0001] The invention relates to a pre-hardened plastic mold steel, which belongs to the field of metal materials. Background technique [0002] 3Cr2MnMo plastic mold steel (P20) standard GB / T1299-2000 C: 0.28~0.40%; Si: 0.20~0.80%; Mn: 0.60~1.00%: Cr: 1.40~2.00%; Mo: 0.30~0.55%; P : ≤0.030%; S≤0.030%. The as-cast structure of the existing 3Cr2MnMo plastic mold steel is mostly coarse flaky F, P and a little M structure. According to the X-ray diffractometer test, F accounts for 86.5%, Fe3C accounts for 10.5%, Cr7C3 and Cr23C6 account for 2.8%, and the remaining M2C accounts for 0.20%. %. During thermal processing and heat treatment, Fe3C, Cr23C6, and Cr7C3 carbides are solid-dissolved into the matrix one after another, and the pinning effect cannot be achieved. Although M2C→M6C+MC has a certain pinning effect, a small amount cannot prevent the appearance of pre-hardened mold steel. Coarse flaky ferrite, sorbite and grain coarsening lead to quality problems ...

Claims

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Application Information

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IPC IPC(8): C22C38/58C22C38/48C21D1/18C21D1/34C21D8/00
Inventor 胡财基
Owner 胡财基
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