Rolling technology and heat treatment method of pre-hardening type plastic die steel

A technology of plastic mold steel and heat treatment method, which is applied in the field of metallurgy, can solve problems such as easy cracking, and achieve the effects of improving hardness uniformity, large market prospects, and enriching variety structure

Inactive Publication Date: 2016-07-13
LIUZHOU IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a normalizing + tempering process instead of quenching and tempering treatment, so as to avoid the problem that the plastic mold steel plate is easy to crack during the quenching process; overcome the weather factors, and can be produced and supplied...

Method used

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  • Rolling technology and heat treatment method of pre-hardening type plastic die steel
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  • Rolling technology and heat treatment method of pre-hardening type plastic die steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Embodiment 1: Rolling process and heat treatment embodiment of LGP20 series:

[0037] The chemical composition of LGP20 series is as follows:

[0038] Chemical composition of LGP20

[0039]

[0040] For LGP20 series blanks, the soaking temperature is controlled at 1200-1250°C, the final rolling temperature is 930-980°C, air-cooled to 380-420°C and then slowly cooled to room temperature; normalized at 890°C, air-cooled to room temperature and then 560-580 ℃ tempering treatment.

[0041] The temperature of the billet in the heating section 1 and 2 of the heating furnace is 1240°C and 1110°C respectively, and the temperature in the soaking section is 1230°C. After the furnace time reaches 258min, the steel is tapped, and the tapping temperature is 1186°C.

[0042] Rolling control conditions: 6 passes of rough rolling, the pass reductions are 18mm, 18mm, 15mm, 26mm, 26mm, 25mm, rolling with a large reduction, and the billet thickness is 82mm; There are 4 passes, the pas...

Embodiment 2

[0048] Embodiment 2: to the rolling process of LG2311 series and heat treatment embodiment:

[0049] Chemical composition of LG2311

[0050]

[0051] The temperature of the billet in the heating section 1 and 2 of the heating furnace is 1230°C and 1109°C respectively, and the temperature in the soaking section is 1228°C. After the furnace time reaches 274min, the steel is tapped, and the tapping temperature is 1181°C.

[0052] Rolling control situation: rough rolling and finish rolling were rolled for 9 passes, of which 5 passes were used for rough rolling, and the pass reductions were 10, 11, 27, 27, 25 respectively. The billet thickness is 120mm; the finishing rolling pass is 4 passes, the pass reductions are 9, 5, 4, 2 respectively, and the finished product specification is 100mm.

[0053] Normalizing control: temperature 870±10°C; time in furnace=2min / mm×thickness+20min (holding time), air cooling.

[0054]

[0055] Tempering control situation: the corresponding te...

Embodiment 3

[0061] Embodiment 3: to the rolling process of LG718 series and heat treatment embodiment:

[0062] Chemical composition of LG718 billet

[0063]

[0064] The temperature of the billet in the heating section 1 and 2 of the heating furnace is 1241°C and 1100°C respectively, and the temperature in the soaking section is 1236°C. After the furnace time reaches 284min, the steel is tapped, and the tapping temperature is 1186°C.

[0065] Control of rolling passes: rough rolling and finish rolling are rolled for 9 passes, of which 7 passes are rough rolled, and the reductions in the last three passes of rough rolling are 28, 27, and 25 respectively, and rolling with large reductions is adopted. The rolled product specification is 36mm.

[0066] Normalizing control: temperature 870±10°C; furnace time=2.5min / mm×thickness+25min (holding time), air cooling.

[0067]

[0068] Tempering control situation: the corresponding tempering temperature has been formulated for different har...

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Abstract

The invention provides a rolling technology and a heat treatment method of pre-hardening type plastic die steel.LGP20 series, LG718 series and LG2311 series steel plates with stock thicknesses of 220 mm are subjected to the rolling technology and heat treatment.A technological process comprises the following steps: plate blank heating, rough scale removal, rough rolling, finish rolling, straightening, cooling after rolling, nibbling shear, stack cooling, flaw detection, steel plate examination, marking, shot blasting, normalizing, stack cooling, shot blasting, tempering, surface checking and performance judging.The rolling technology and the heat treatment method of the pre-hardening type plastic die steel have the advantages that an optimal heating technology is determined, and influence of casting blank segregation to steel segregation is reduced; by normalizing and tempering technologies, a structure form similar to thermal refining is obtained, and the problem that a plastic die steel plate is easy to crack in a quenching process is avoided; through large-rolling-reduction rough rolling, compactness of the structure of a steel plate is improved, and internal shrinkage of the steel plate is reduced; cooling is controlled reasonably after rolling and normalizing, the ideal structure is obtained, and cracking of the steel plate is avoided; and weather factors are overcome, and goods can be produced and supplied all the year round.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a rolling process and heat treatment method of pre-hardened plastic mold steel. Background technique [0002] In the past 40 years, with the rapid development of the petrochemical industry, the output of plastics has increased rapidly. Many plastic products must be molded into shape. Molds are consumables with a large amount of consumption, which has prompted the development and opening of some special plastic mold steels at home and abroad. These special steel types are combined with some traditional steel types to form a series of plastic mold steels, including carbon plastic mold steel, pre-cast Hard plastic mold steel, corrosion-resistant plastic mold steel, permeable plastic mold steel, etc. It is expected that in the next few years, my country's die steel industry will have a large room for development, especially in the field of high-end products. In the future, dome...

Claims

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Application Information

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IPC IPC(8): C21D8/02
CPCC21D8/0205C21D8/0226C21D8/0263
Inventor 沈敏卢春宁罗永恒覃永国李志鑫文宪刚
Owner LIUZHOU IRON & STEEL
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