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Low-strength martensitic stainless steel ring forging and its forging method

A martensitic stainless steel and ring forging technology, applied in the field of martensitic stainless steel, can solve the problems of low tensile strength and unattainable QT650, and achieve the effect of improving the qualification rate and avoiding energy waste

Active Publication Date: 2020-05-15
AVIC EXCELLENCE FORGING WUXI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are few researches on X3CrNiMo13-4 in China, and the European standard medium strength grades QT780 and QT900 are easy to achieve, but QT650 cannot.
A few days ago, our company received a batch of orders from large foreign hydropower companies, requiring product performance to meet the QT650 level. After a large number of tests, they were unable to meet the requirements. The minimum tensile strength made in the test was 850Mpa

Method used

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  • Low-strength martensitic stainless steel ring forging and its forging method
  • Low-strength martensitic stainless steel ring forging and its forging method

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Embodiment 1

[0040] This embodiment provides a low-strength martensitic stainless steel ring forging, the chemical composition of which is shown in Example 1 in Table 1. The strength grade of the martensitic stainless steel ring forging is QT650. Tensile strength: 650~830Mpa, yield strength ≥520Mpa, elongation ≥15%, made by the following forging methods:

[0041] The steel ingot is made by vacuum degassing ingot casting, and then the steel ingot is forged. The specific steps are as follows:

[0042] a. Pre-forging heating: put the steel ingot into the gas furnace, heat treatment in sections, reduce the temperature difference between the inside and outside of the steel ingot, and avoid cracking: first heat up to 600 °C at a rate of 80 °C / h or less, and keep it for 3 hours; Equal to 80°C / h heating up to 850°C, holding for 5h; then heating at 120°C / h or less to 1160°C, holding for 7h, to avoid cracking of the forging billet caused by δ ferrite caused by excessive heating temperature, and then s...

Embodiment 2

[0052] This embodiment provides a low-strength martensitic stainless steel ring forging, the chemical composition ratio of which is shown in Example 2 in Table 1. The strength grade of the martensitic stainless steel ring forging is QT650. Tensile strength: 650~830Mpa, yield strength ≥520Mpa, elongation ≥15%, made by the following forging methods:

[0053] The steel ingot is made by vacuum degassing ingot casting, and then the steel ingot is forged. The specific steps are as follows:

[0054] a. Pre-forging heating: put the steel ingot into the gas furnace, heat treatment in sections, reduce the temperature difference between the inside and outside of the steel ingot, and avoid cracking: first heat up to 600 °C at a rate of 80 °C / h or less, and keep it for 3 hours; Equal to 80°C / h heating up to 850°C, holding for 5h; then heating up to 1165°C at 120°C / h or less, holding for 8h, to avoid cracking of the forging billet caused by δ ferrite caused by excessive heating temperature,...

Embodiment 3

[0064] This embodiment provides a low-strength martensitic stainless steel ring forging, the chemical composition of which is shown in Example 3 in Table 1. The strength grade of the martensitic stainless steel ring forging is QT650. Tensile strength: 650~830Mpa, yield strength ≥520Mpa, elongation ≥15%, made by the following forging methods:

[0065] The steel ingot is made by vacuum degassing ingot casting, and then the steel ingot is forged. The specific steps are as follows:

[0066] a. Pre-forging heating: put the steel ingot into the gas furnace, heat treatment in sections, reduce the temperature difference between the inside and outside of the steel ingot, and avoid cracking: first heat up to 600 °C at a rate of 80 °C / h or less, and keep it for 3 hours; Equal to 80°C / h heating up to 850°C, holding for 5h; then heating up to 1175°C at ≤ 120°C / h, holding for 7h, to avoid cracking of the forging billet caused by δ ferrite caused by excessive heating temperature, and then st...

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Abstract

The invention discloses a low strength martensitic stainless steel ring forge piece and a forging method thereof. The martensitic stainless steel is prepared from the following components in percentage by weight: less than or equal to 0.05% of C, less than or equal to 0.05% of Si, 0.50-1.00% of Mn, less than or equal to 0.030% of P, less than or equal to 0.015% of S, 12-14% of Cr, 0.30-0.70% of Mo, 4.00-4.50% of Ni, 0.020-0.040% of N, less than or equal to 0.08% of V, less than or equal to 0.03% of Nb, less than or equal to 0.03% of Ti and the balance of Fe and impurities. The forging processcomprises the following steps: firstly, carrying out drawing-out and pre-forging; and then, carrying out cold saw blanking for upsetting for three times and drawing for two times, chambering a mandrelsupporter and rolling a ring, wherein the initial forging temperature is 1160-1180 DEG C, the finish forging temperature is 900 DEG C, and the finishing temperature can be properly reduced by 30-60 DEG C. In this way, according to the low strength martensitic stainless steel ring forge piece and the forging method thereof, an X3CrNiMo13-4 / QT650 forge piece meeting the demand on standard performance is developed by optimizing the chemical components of raw materials and matching with a reasonable thermal treatment system, so that zero breakthrough of low strength and low hardness products canbe achieved by means of the material, the primary qualification pass rate of the product is 100%, and energy source waste caused by rework and repair is avoided.

Description

technical field [0001] The invention relates to the technical field of martensitic stainless steel, in particular to a low-strength martensitic stainless steel ring forging and a forging method thereof. Background technique [0002] Martensitic stainless steel X3CrNiMo13-4 / QT650 is European standard EN10250-4 material, strength grade QT650 is Rm: 650-830Mpa, R P0.2 ≥520Mpa, A≥15%. [0003] Super martensitic stainless steel X3CrNiMo13-4 is widely used in energy fields such as hydropower, offshore oil, natural gas platforms, nuclear power and petrochemical industries. It is mainly used in the manufacture of core components of energy equipment. X3CrNiMo13-4 has excellent plasticity corrosion performance. [0004] At present, there are few domestic researches on X3CrNiMo13-4, and the European standard medium strength grades QT780 and QT900 are easy to achieve, but QT650 cannot. A few days ago, our company received a batch of orders from large foreign hydropower companies, req...

Claims

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Application Information

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IPC IPC(8): C22C38/04C22C38/02C22C38/44C22C38/46C22C38/48C22C38/50C21D8/00
CPCC21D8/005C21D2211/008C22C38/001C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/50
Inventor 李同涛郭亮朱建鑫任益新沈志远吴燕芬
Owner AVIC EXCELLENCE FORGING WUXI
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