Mirror large-die-block preparing and producing method of 4Cr16Mo die

Abstract

It is a new preparation and production method of corrosion-resistant and anti-abrasive plastic die steel 4Cr16Mo and its big mirror module. The characteristic is about its chemical composition. There are 0.33-0.43%C, 0.30-1.00%Mn, 0.30-1.00%Si, less than 0.045%S, less than 0.045%P, 14-18%Cr, 0.10-1.00%Ni, 0.80-1.50%Mo besides Fe. The method includes double refinement consisting of the primer smelting in electric furnace and vacuum handling outside the furnace and electroslag remelting, and necessary stress relieving annealing static ingot and electroslag ingot to refine electroslag ingot of component-uniform. After that, it uses hot machining forging technology and necessary stress relieving annealing of module to make the electroslag ingot into big module (thickness: 500mm, width:1200mm, length: 2500mm). At last, special heat-treat module modified treatment technology is used to bring out big highly corrosion-resistant and highly anti-abrasive plastic die steel module. This kind of module has stable quality and the nature reaching the standard(dirty component A<=2.0, B<=2.0, C thinness<=2.0, C thickness<=1.5, D<=2.0). To sum up, it has significant economic and social efficiency.

Description

technical field [0001] The invention relates to the compositional alloying design of mold steel in the metallurgical industry, in particular to a production method for corrosion-resistant and wear-resistant plastic mold steel and modules thereof. Background technique [0002] Die steel is a special alloy steel, which can be generally divided into three categories: cold work die steel, hot work die steel and plastic mold steel. Steel for plastic molds is mainly used to produce plastic forming molds or mold bases with large batch size, large mold size, complex shape, high dimensional accuracy and surface roughness; hot work mold steel is mainly used for manufacturing Dies for hot working of metals, including hot forging dies (such as 5CrNiMo module steel), etc. Therefore, the die steel for manufacturing modular forgings usually includes steel for plastic dies and some hot work die steels (such as 5CrNiMo die steel). Module is a conventional product of plastic mold steel, mai...

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Problems solved by technology

[0003] my country's plastic mold steel research started late, and the research on corrosion-resistant mold materials is even poorer. At present, the basic steel grades of domestic corrosion-resistant plastic mold steel are mainly 9Cr18, Cr18MoV, 4Cr13, 1Cr17Ni2 and other steel varieties. In production practice, the above steel grades There are the following defects: (1) 9Cr18 and Cr18MoV belonging to ledeburite steel, due to the high carbon content, there are primary and secondary composite carbides in the as-cast structure, such as (Fe, Cr) 7C3, so the module production must pass Forging with a large amount of compression can make the coarse carbides evenly distributed (otherwise there will be a chain-like distribution of carbides in the structure); and the size of the large module is large, even if the forging process of repeatedly thickening and elongating is used, it is difficult to ensure the core of the material. Complete crushing of internal carbides and uniform distribution of carbides (affecting the corrosion resistance and wear resistance of the module)

(2) 4Cr13 belongs to hypereutectoid steel (when the Cr content is 12%, the S point moves to the left, that is, the eutectoid point moves to the left, and the eutectoid carbon content moves to 0.4%), the heat treatment and quenching temperature of the steel is 1060 When the temperature is above -1100°C, the carbides cannot be completely dissolved, and it is difficult to reach a chromium content of about 11%-12% in the martensite after quenching; because the Cr content is not high, the mass fraction of the components required for corrosion resistance cannot be met. The corrosion resistance of steel is poor, and it can only resist general atmospheric and water vapor corrosion (although high hardness and wear resistance can be obtained after heat treatment, it can only be used for the manufacture of plastic molds with general corrosion resistance)

(3) 1Cr17Ni2 steel, which is a martensitic stainless and acid-resistant steel, has good corrosion resistance when used for oxidizing acids, nitric acid with a certain temperature and concentration, most organic acids and salt solutions; However, there are disadvantages such as brittle tendency, complex thermal processing technology, chemical composition segregation and microscopic fluctuations have a great influence on steel structure and properties, and poor welding performance.

[0004] To sum up, for the manufacture of plastic mold steels such as stamping dies and die-casting molds with high corrosion resistance and high wear resistance, among the basic steel grades of domestic corrosion-resistant plastic mold steels, there are generally processing difficulties and poor quality. Defects of poor stability or inability to have both corrosion resistance and wear resistance; In addition, relevant domestic and foreign materials have been retrieved, and for modules of corrosion-resistant and wear-resistant plastic mold steel (hardness range: HRC30-40, hardness fluctuation 4HRC), large The heat treatment process of the module (thickness: 200-500mm; width: 800-1200mm; length > 2500mm) has not been reported

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