CN105063310A - Structure ultra-fine treatment process for high-chromium corrosion-resistant plastic mould steel - Google Patents

Abstract

The invention belongs to the technical field of corrosion-resistant plastic mould steel, and particularly relates to a structure ultra-fine treatment process for high-chromium corrosion-resistant plastic mould steel. The process comprises the following specific steps: A, carrying out high-temperature diffusion treatment: carrying out high-temperature diffusion on steel ingot for 5-25 hours at a high temperature of 1200-1250 DEG C after the steel ingot is forged and broken down; and B, carrying out fine treatment: heating a workpiece to 980-1050 DEG C and preserving the temperature at 20-200s/mm, quickly cooling the workpiece to 200-700 DEG C at a rate of 80-800 DEG C/h, then, heating the workpiece to 800-900 DEG C at a rate of 40-100 DEG C/h, then slowly cooling the workpiece to a temperature below 600 DEG C at a rate of 5-50 DEG C/h, and discharging the workpiece out of a furnace to carry out air-cooling. The invention provides the structure ultra-fine treatment process, by which structure segregation is improved, quantities of eutectic carbides and network carbides are reduced and a fine and uniform spheroidized annealing tissue is obtained, for the high-chromium corrosion-resistant plastic mould steel.

Description

A kind of microstructure ultra-fining treatment treatment process of high chromium corrosion-resistant plastic die steel

Technical field

The invention belongs to corrosion-resistant plastic die steel production technical field, be specifically related to a kind of microstructure ultra-fining treatment treatment process of high chromium corrosion-resistant plastic die steel.

Background technology

Corrosion-resistant plastic die steel mainly for the manufacture of the mould to plastic shaping, as panel of LCD mould, appliance shell mould etc.Part mould requires very strict to corrosion resistance nature and mirror polish performance at work.Therefore, in order to meet operating mode service requirements, require that moulding stock should have good microstructure uniformity energy.The tissue of high chromium corrosion resistant mould steel on the polishing performance of material and the impact of corrosion resistance nature most important, the size of annealed structure homogeneity, Aliquation carbide, carbide network, form and distribution situation, all have extreme influence to the use of die steel.High chromium corrosion-resistant plastic die steel belongs to hypereutectoid steel, and molten steel easily produces choosing point crystallization in process of setting, produces more serious component segregation.In the central zone of the respective regions of ingot casting, particularly final set, carbon and alloying element are enriched to eutectic composition, occur the secondary carbide network of a small amount of unbalanced substable eutectic carbide and the slow Intergranular precipitation distribution of cooling after forged.The pretreatment process of current routine is that workpiece is warming up to 850 ~ 890 DEG C of insulation 2min/mm with stove, is then chilled to 500 DEG C of air coolings of coming out of the stove with stove, does not have obvious effect to the dissolving improving banded segregation and hypoeutectic carbide and secondary carbide network.

Summary of the invention

The object of the invention is that overcoming above-mentioned deficiency of the prior art provides a kind of microstructure ultra-fining treatment treatment process improving microstructure segregation, minimizing eutectic carbides and carbide network quantity, obtain the high chromium plastic die steel of the Spheroidizing Annealing tissue of fine uniform.

Technical scheme of the present invention is achieved in that a kind of microstructure ultra-fining treatment treatment process of high chromium corrosion-resistant plastic die steel, and the concrete steps of this technique are as follows:

A, High temperature diffusion process: steel ingot after hammer cogging at 1200 ~ 1250 DEG C of High temperature diffusion 5 ~ 25h;

B, thinning processing: workpiece is warming up to 980 ~ 1050 DEG C of insulation 20 ~ 200s/mm, 200 ~ 700 DEG C are quickly cooled to the speed of 80 ~ 800 DEG C/h, then be warming up to 800 ~ 900 DEG C with the speed of 40 ~ 100 DEG C/h, then slowly cool to less than 600 DEG C air coolings of coming out of the stove with the speed of 5 ~ 50 DEG C/h.

The positively effect that technical scheme of the present invention produces is as follows: steel ingot be incubated at 1200 ~ 1250 DEG C of High temperature diffusion 5 ~ 25h after hammer cogging, through forging broken Aliquation carbide through dissolving diffusion for a long time, disappears or change tiny.After forging, workpiece is warming up to 980 ~ 1050 DEG C of insulation 20 ~ 200s/mm, 200 ~ 700 DEG C are cooled to the speed of 80 ~ 800 DEG C/h after reaustenitizing, obtain shred layer pearlitic structure, crystal grain also obtains refinement, then 800 ~ 900 DEG C are warming up to the speed of 40 ~ 100 DEG C/h, grain boundaries forms new small grains, part crystal boundary secondary carbide network fusing simultaneously, less than 600 DEG C air coolings of coming out of the stove are slowly cooled to subsequently with the speed of 5 ~ 50 DEG C/h, the carbide of vanadium and the carbide of chromium are spherical or point-like even dispersion is separated out, thus obtain the tiny and Spheroidizing Annealing tissue of carbide fine uniform of crystal grain.

Embodiment

With specific embodiment, technical scheme of the present invention is described below, but protection scope of the present invention is not limited thereto.

Embodiment one

A kind of high chromium corrosion-resistant plastic die steel organize miniaturization pretreatment technology, model is 4Cr13NiVSi die steel, ingot shape is 5T, steel ingot heats in gas-fired car bottom furnace, and return after hammer cogging at 1200 ~ 1250 DEG C of High temperature diffusion 25h in gas furnace, forging of coming out of the stove is to final dimension 200mm(thickness) × 710mm(width) × 3500mm(length).

Subsequently by workpiece heat to 1030 ± 10 DEG C, be quickly cooled to 200 ~ 700 DEG C by 150 DEG C/h, after being then warming up to 860 DEG C by the speed of 30 DEG C/h, be incubated 140s/mm, be finally chilled to 500 DEG C of air coolings of coming out of the stove with 30 DEG C/h with stove.

In the sampling of workpiece cross section centre, detecting annealed structure according to GB/T1299-2014 is 3 grades, carbides-free liquation, carbide network 2 grades, autstenitic grain size 8 grades.

embodiment two

A microstructure ultra-fining treatment treatment process for high chromium corrosion-resistant plastic die steel, model is 1.2316 die steel, and ingot shape is 9T.

Steel ingot heats in gas-fired car bottom furnace, and returns after hammer cogging at 1200 ~ 1250 DEG C of High temperature diffusion 25h in gas furnace, and forging of coming out of the stove is to final dimension 300mm(thickness) × 910mm(width) × 3500mm(length).

Subsequently by workpiece heat to 1000 ± 10 DEG C, be quickly cooled to 400 ~ 700 DEG C with 150 DEG C/h, after being then warming up to 870 DEG C by the speed of 30 DEG C/h, be incubated 140s/mm, be finally chilled to 500 DEG C of air coolings of coming out of the stove with 30 DEG C/h with stove.

In the sampling of workpiece cross section centre, detecting annealed structure according to GB/T1299-2014 is 3 grades, carbide liquid-extraction 2 grades, carbide network 3 grades, autstenitic grain size 7 grades.

Claims (1)

1. a microstructure ultra-fining treatment treatment process for high chromium corrosion-resistant plastic die steel, is characterized in that: the concrete steps of this technique are as follows:

A, High temperature diffusion process: steel ingot after hammer cogging at 1200 ~ 1250 DEG C High temperature diffusion 5 ~ 25h;

B, thinning processing: workpiece is warming up to 980 ~ 1050 DEG C of insulation 20 ~ 200s/mm, 200 ~ 700 DEG C are quickly cooled to the speed of 80 ~ 800 DEG C/h, then be warming up to 800 ~ 900 DEG C with the speed of 40 ~ 100 DEG C/h, then slowly cool to less than 600 DEG C air coolings of coming out of the stove with the speed of 5 ~ 50 DEG C/h.