Medium-carbon steel large diesel engine output shaft hardening and tempering process

A diesel engine and output shaft technology, which is applied in the direction of manufacturing tools, furnace types, heat treatment equipment, etc., to avoid cracking and deformation out of tolerance, reduce the temperature difference between inside and outside, and increase the amount of solid solution

Active Publication Date: 2014-03-05
CSSC MARINE POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The conventional quenching and tempering process is not suitable for quenching and tempering heat treatment of large shaft forgings, and a new quenching and tempering process needs to be redesigned

Method used

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  • Medium-carbon steel large diesel engine output shaft hardening and tempering process
  • Medium-carbon steel large diesel engine output shaft hardening and tempering process
  • Medium-carbon steel large diesel engine output shaft hardening and tempering process

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Embodiment Construction

[0018] The present invention will be further described below in conjunction with drawings and embodiments.

[0019] The cross-sectional size of the output shaft of the large diesel engine in this embodiment is about 220mm, its mass is about 1000Kg, and its material is #45 forging. Such as figure 1 As shown, this embodiment includes the following steps:

[0020] (1) normalizing

[0021] Put the rough-processed large diesel engine output shaft into the trolley furnace at room temperature, raise the temperature in stages, keep it at 350±20°C and 600±20°C for 1 hour, and then raise the temperature to 870±20°C for 4-4.5 hours; After the heat preservation is completed, the output shaft of the large diesel engine is hoisted out, and cooled to room temperature with a fan.

[0022] (2) three quenching

[0023] The output shaft of the large diesel engine is put into the trolley furnace again at room temperature, and the temperature is raised in stages, and the temperature is kept at...

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Abstract

The invention discloses a medium-carbon steel large diesel engine output shaft hardening and tempering process. The process comprises the following steps: (1) normalizing: filling an output shaft in a furnace, heating to the temperature of 350 +/-20 DEG C and 600+/-20 DEG C in a staged way, preserving the heat, hanging out the output shaft, blowing cold air to cool the output shaft to room temperature by using a fan; (2) quenching for three times: filling the output shaft into the furnace again, heating to the temperature of 350 +/-20 DEG C, 600+/-20 DEG C and 850+/- 10 DEG C in a staged way; cooling by air and then cooling in a water tank, cooling by the air again and cooling by water again, and then cooling in an oil tank; (3) high-temperature tempering: tempering at the temperature of 565+/- 10 DEG C, preserving the temperature and cooling by the air out of the furnace. By the process, the surface martensite transformation speed at the first stage of a large shaft forging is improved, and the surface quenching hardness of the large shaft forging is improved by adopting the reasonable quenching cooling mode of air cooling-water cooling-air cooling-water cooling-oil cooling. The difference between the inside temperature and the outside temperature of the large shaft forging is reduced by the air cooling adopted by the process, and the cracking tendency of the large shaft forging is effectively reduced.

Description

technical field [0001] The invention relates to a heat treatment process for a large shaft forging after rough machining, in particular to a quenching and tempering process for a large diesel engine output shaft made of medium carbon steel, and belongs to the technical field of metal heat treatment. Background technique [0002] Large-scale diesel engine output shafts generally use forged blanks. This large-scale shaft forging needs quenching and tempering treatment after rough machining to improve its comprehensive mechanical properties and meet the requirements of diesel engine output shafts under alternating stress conditions. [0003] Due to the large cross-sectional effective size and mass of such large shaft forgings, according to the "size effect" and "mass effect" of the heat treatment process, the conventional quenching and tempering process is prone to the relatively large surface hardening depth of such large shaft forgings. Shallow, large residual tensile stress ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/25C21D9/28
Inventor 朱松东徐飞庄振武连兴旺
Owner CSSC MARINE POWER
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