Thermal treatment process for 40CrNiMoA core rod and 40CrNiMoA core rod obtained through process

A mandrel and process technology, which is applied in the field of forging, can solve the problems of difficult impact toughness and other problems, and achieve the effects of improving grain size, avoiding cracking of workpieces, and reducing quenching stress

Active Publication Date: 2014-06-11
HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main factors affecting the service life of the mandrel are the strength limit and impact toughness of the material. Only when the two are combined to obtain the best comprehensive mechanical properties can the service life of the mandrel be greatly improved. Therefore, the user requires the mechanical properties of the mandrel after heat treatment To meet the performance index of GB / T 3077 standard small and medium-sized samples after heat treatment, but when the 40CrNiMoA mandrel is heat-treated and produced according to the conventional water quenching and oil cooling process, its impact toughness is difficult to meet the standard requirements

Method used

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  • Thermal treatment process for 40CrNiMoA core rod and 40CrNiMoA core rod obtained through process
  • Thermal treatment process for 40CrNiMoA core rod and 40CrNiMoA core rod obtained through process
  • Thermal treatment process for 40CrNiMoA core rod and 40CrNiMoA core rod obtained through process

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Experimental program
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Effect test

Embodiment 1

[0025] Such as figure 1 Shown, a kind of heat treatment process of 40CrNiMoA mandrel, it comprises the following steps:

[0026] Step 1. Normalizing treatment: Put the 40CrNiMoA mandrel into the furnace with a furnace temperature of 450°C, heat it to the normalizing temperature of 860°C with full power, and keep it warm for 1 hour per 100mm of the effective cross-sectional diameter of the 40CrNiMoA mandrel. After 10 minutes, air-cool to room temperature;

[0027] Step 2, quenching treatment: put the 40CrNiMoA mandrel after the normalizing treatment in step 1 into the furnace at a furnace temperature of 450°C, then heat it to the quenching temperature of 840°C with full power, and keep it warm for 1 hour per 100mm of the effective cross-sectional diameter of the 40CrNiMoA mandrel , the furnace is cooled to the surface temperature of the 40CrNiMoA mandrel at 100-140°C by the gap cooling method of water ~ air ~ water to obtain the martensitic structure;

[0028] Step 3, temperi...

Embodiment 2

[0040] A kind of heat treatment process of 40CrNiMoA mandrel, it comprises the steps:

[0041] Step 1. Normalizing treatment: Put the 40CrNiMoA mandrel into the furnace with a furnace temperature of 620°C, heat it to the normalizing temperature of 870°C with full power, and keep it warm for 0.9h per 100mm of the effective cross-sectional diameter of the 40CrNiMoA mandrel. After cooling for 10 minutes, air-cool to room temperature;

[0042] Step 2, quenching treatment: put the 40CrNiMoA mandrel after the normalizing treatment in step 1 into the furnace at a furnace temperature of 600°C, then heat it with full power to the quenching temperature of 850°C, and keep it warm for an effective cross-sectional diameter of 0.9 per 100mm of the 40CrNiMoA mandrel. h, after being released from the furnace, the surface temperature of the 40CrNiMoA mandrel is 100-140° C. to obtain a martensitic structure;

[0043] Step 3, tempering treatment: put the 40CrNiMoA mandrel after the quenching tr...

Embodiment 3

[0055] A kind of heat treatment process of 40CrNiMoA mandrel, it comprises the steps:

[0056] Step 1. Normalizing treatment: Put the 40CrNiMoA mandrel into the furnace with a furnace temperature of 650°C, heat it to the normalizing temperature of 880°C with full power, and keep it warm for 0.8h per 100mm of the effective cross-sectional diameter of the 40CrNiMoA mandrel. After cooling for 10 minutes, air-cool to room temperature;

[0057] Step 2, quenching treatment: put the 40CrNiMoA mandrel after the normalizing treatment in step 1 into the furnace at a furnace temperature of 650°C, then heat it at full power to the quenching temperature of 860°C, and keep it warm for an effective cross-sectional diameter of 0.8 per 100mm of the 40CrNiMoA mandrel. h, after being released from the furnace, the surface temperature of the 40CrNiMoA mandrel is 100-140° C. to obtain a martensitic structure;

[0058] Step 3, tempering treatment: Put the 40CrNiMoA mandrel after the quenching trea...

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Abstract

The invention belongs to the field of forging technology, and particularly relates to a thermal treatment process for a 40CrNiMoA core rod and the 40CrNiMoA core rod obtained through treatment. The thermal treatment process comprises three processes, namely normalizing treatment, quenching treatment and tempering treatment, and the 40CrNiMoA core rod is obtained through the three processes. The thermal treatment process adopts the method of normalizing and quenching; through normalizing and accelerating cooling after normalizing, the as-forged particle size can be improved and thick lamellar pearlite can be eliminated, so that quenching is ready; the water-air-water gap cooling method is adopted when quenching cooling is performed, initial water temperature and temperature rise in the process of cooling are strictly controlled; enough quenching severity of a wokpiece is guaranteed to obtain so that a martensitic structure is obtained, while the quenching stress is reduced to the maximum to avoid cracking of the workpiece due to too large stress; a fine and even tempered sorbite is obtained by virtue of high-temperature quenching; relatively high impact toughness is obtained while the high strength is guaranteed; the thermal treatment process has the advantages of being high in production efficiency and low in rejection rate, and improving the impact toughness while ensuring the high strength.

Description

technical field [0001] The invention belongs to the technical field of forging, and in particular relates to a heat treatment process of a 40CrNiMoA mandrel of an Accu_RoLL rolling mill and a 40CrNiMoA mandrel obtained by the treatment. Background technique [0002] At present, domestic production of seamless steel pipe units is mainly based on "longitudinal deformation continuous rolling mill" and "transverse deformation Accu_RoLL rolling mill" as the main production forms. The Accu_RoLL rolling mill is favored by domestic private seamless steel pipe manufacturers for its low investment, short construction period and wide range of product production. According to statistics, there are currently 15 sets of Accu_RoLL pipe rolling units in China, with an annual output of 3 million tons of steel pipes and an annual consumption of 2,000 tons of mandrels. At present, the mandrel materials for Accu_RoLL rolling mill mainly include H13 steel and 40CrNiMoA steel, among which 40CrNi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/00B21B25/00C22C38/44
Inventor 赵颖赵玉
Owner HENAN ZHONGYUAN SPECIAL STEEL EQUIP MFG CO LTD
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