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Superhigh-temperature crossed large-deformation forging method for improving structure uniformity of tool and mold steel

A technology with uniform structure and tool steel, which is applied in the forging field of tool steel to achieve the effect of eliminating shrinkage porosity, solving shrinkage cavity and improving metallurgical quality

Active Publication Date: 2016-03-30
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the central defects and internal quality problems of tool and die steel ingots in the current industrial production, the purpose of the present invention is to provide an ultra-high temperature cross-large deformation forging method that improves the uniformity of tool and die steel structure, which can effectively eliminate the shrinkage cavity and porosity of steel ingots. Reduce metallurgical defects such as dendrite segregation, refine the structure, and improve the metallurgical quality and mechanical properties of forgings

Method used

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  • Superhigh-temperature crossed large-deformation forging method for improving structure uniformity of tool and mold steel
  • Superhigh-temperature crossed large-deformation forging method for improving structure uniformity of tool and mold steel
  • Superhigh-temperature crossed large-deformation forging method for improving structure uniformity of tool and mold steel

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Experimental program
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Effect test

Embodiment 1

[0067] The weight of the steel ingot for smelting and casting is 14 tons, the cross section is circular, the size is Φ750×4000mm, and the material is H13 steel. The measured composition is shown in Table 1.

[0068] The chemical composition (weight percent, %) of H13 steel in the embodiment 1 of table 1

[0069] element C Si mn P S Cr Mo Ni V Fe Measured ingredients 0.38 0.92 0.38 0.011 0.002 5.32 1.41 0.14 1.04 Remain

[0070] Cut the steel ingot into two sections from the middle, and the low-magnification structure of the section is as follows: image 3 (a) shown. Take the part close to the riser end for super-high temperature with liquid core cross large deformation forging, the specific steps are as follows:

[0071] The first step is ultra-high temperature demoulding. 2.5 hours after pouring the steel ingot, blow off the protective slag from the riser to release the steel ingot with a liquid core at an ultra-high temperature...

experiment example 1

[0089] For the H13 forgings in Example 1 and Comparative Example 1, saw along the middle, take a cross-sectional low-magnification test piece, and corrode it with nitric acid alcohol. For the specific low-magnification structure, see image 3 (b) and image 3 (c). It can be seen from the figure that forging by conventional method, the original as-cast defects failed to heal, but formed shrinkage cracks in the core, and there were also inhomogeneities in the structure. In contrast, the forging billet with a very dense and uniform internal structure can be obtained by using the ultra-high temperature cross-over large deformation forging method with a liquid core.

[0090] For the H13 forgings in Example 1 and Comparative Example 1, carry out isothermal spheroidization treatment, keep them warm at 850°C and 750°C for 5h, slowly cool to room temperature, take the central sample of the forging, and use a metallographic microscope to analyze the structure of the sample. Analysis, ...

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Abstract

The invention relates to the field of forging of tool and mold steel, in particular to a superhigh-temperature crossed large-deformation forging method for improving the structure uniformity of tool and mold steel. The superhigh-temperature crossed large-deformation forging method for improving the structure uniformity of the tool and mold steel comprises the steps that firstly, superhigh-temperature demolding is conducted on a poured steel ingot belt liquid core; secondly, the steel ingot belt liquid core is placed in a insulated van for temperature uniformization and conveyed to a forging press, and three-direction crossed large-deformation forging is conducted on the steel ingot belt liquid core, so that branch crystals formed at the tail stage of solidification are sufficiently crushed, a large quantity of isometric crystal structures are formed, shrinkage cavities and looseness are eliminated, and dendritic segregation is relieved; and finally, conventional forging formation including upsetting, drawing-out and the like is conducted. According to the superhigh-temperature crossed large-deformation forging method for improving the structure uniformity of the tool and mold steel, a conventional method that forging is conducted after a die-cast steel ingot is completely solidified is broken, and a semi-solid structure with the steel ingot core having excellent fluidity and a huge surface and core temperature difference are created through superhigh-temperature demolding of the belt liquid core; forced feeding and pressure solidification are achieved through a three-direction crossed large-deformation method, and the developed branch crystals formed at the tail stage of the solidification of a tool and mold steel ingot are effectively crushed; central hole defects are overcome through welding, the problems of shrinkage cavities, looseness, segregation and the like are completely solved, and the metallurgical quality of products is improved.

Description

technical field [0001] The invention relates to the forging field of tool and die steel, in particular to an ultra-high temperature band liquid core crossing large deformation forging method for improving the microstructure uniformity of die casting tool and die steel (steel billet). Background technique [0002] The mold industry is a leading industry and the basis for the development of other industries. It is known as the "mother of industry" and is an important symbol to measure the industrial level of a country and region. It is of great significance to improve the intrinsic quality of tool steel and ensure its safety and reliability during operation. [0003] Tool and die steel is generally divided into three categories: hot work, cold work, and mold steel for injection molding. Although the use environment is different, they are generally relatively harsh. The mold needs to withstand external factors such as high temperature, high pressure, corrosion, and wear. The c...

Claims

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Application Information

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IPC IPC(8): B21J5/00B21J5/08B21J1/00B22D29/04B22D7/06
Inventor 孙明月徐斌栾义坤刘宏伟康秀红傅排先李殿中李依依
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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