38CrMoAl nitrided steel with nitrided layer low in fragility

A technology of nitriding layer and nitriding steel, which is applied in the field of brittle 38CrMoAl nitriding steel with low nitriding layer, which can solve the problems of high brittleness of the nitriding layer, achieve enhanced nitriding performance, increase production and use costs, and reduce stress levels Effect

Inactive Publication Date: 2015-11-25
SHOUGANG CORPORATION
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The object of the present invention is to provide a kind of 38CrMoAl nitriding steel with low nitriding layer brittleness, which solves the problem of high brittleness of the nitriding layer of existing 38CrMoAl steel

Method used

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  • 38CrMoAl nitrided steel with nitrided layer low in fragility
  • 38CrMoAl nitrided steel with nitrided layer low in fragility
  • 38CrMoAl nitrided steel with nitrided layer low in fragility

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Embodiment 1 and Embodiment 2

[0027]Prepare the nitriding steel of the present invention and the comparison steel according to the following method: use a 50kg vacuum smelting furnace to smelt a square ingot with a cross section of 125mm×125mm, forge it into a Φ25mm round bar after surface grinding, and carry out normalizing and quenching and tempering treatments on the forged material , intercept the sample block for nitriding treatment. The composition mass percentages of the steel grades obtained from smelting are shown in Table 1. The conventional gas hard nitriding process is adopted. The nitriding process is two-stage nitriding. The first stage is nitriding at 490°C for 30 hours, the ammonia decomposition rate is 15-20%, and the second stage is nitriding at 520°C for 60 hours. The ammonia decomposition rate is 30-40%. The gas hard nitriding process has a long nitriding time and a large depth of the nitriding layer, and the nitriding layer has a higher brittleness tendency, so it is easier to disting...

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Abstract

The invention discloses 38CrMoAl nitrided steel with a nitrided layer low in fragility and belongs to the technical field of alloy steel. The 38CrMoAl nitrided steel with the nitrided layer low in fragility comprises, by mass, 0.35%-0.42% of carbon, 0.20%-0.45% of silicon, 0.30%-0.60% of manganese, 1.35%-1.65% of chromium, 0.15%-0.25% of molybdenum, 0.70%-1.10% of aluminum, 0%-0.015% of phosphorus, 0%-0.010% of sulphur, 0.001%-0.01% of vanadium, 0.001%-0.01% of niobium, 0.001%-0.01% of titanium, 0.0020%-0.006% of nitrogen, 0.0005%-0.0025% of oxygen and the balance iron and other inevitable impurities. The 38CrMoAl nitrided steel with the nitrided layer low in fragility has the advantages that under the same nitriding process, the fragility of the nitrided layer can be reduced, and production cost and use cost are not increased obviously.

Description

technical field [0001] The invention belongs to the technical field of alloy steel, in particular to a brittle 38CrMoAl nitrided steel with a low nitrided layer. Background technique [0002] Nitriding steel is steel for surface nitriding, adding 2 or more kinds of nitride-forming elements such as Al, Cr, Mo, V, etc., so it is very suitable for nitriding; steel has high surface hardness and good wear resistance after nitriding , The advantages of strong toughness and certain corrosion resistance in the heart. 38CrMoAl steel is a kind of alloy structural steel in GB / T3077-1999. It is the only special nitriding steel in the national standard. ˜1.65 wt% Cr, 0.15˜0.25 wt% Mo, 0.7˜1.10 wt% Al, ≤0.025 wt% P, ≤0.015 wt% S, ≤0.025 wt% Cu, ≤0.030 wt% Ni. The surface hardness of 38CrMoAl after nitriding is above 920HV (about 67HRC), and the pretreatment is quenching and tempering (usually the quenching and tempering hardness requirement is ≥ 260HB). [0003] After surface treatment...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/28
Inventor 马跃佟倩陈京生孙齐松罗志俊吕迺冰王立峰崔京玉
Owner SHOUGANG CORPORATION
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