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Super-conventional performance heat treatment process for large axial forgings of carbon steel

A carbon steel and shaft technology, used in heat treatment furnaces, heat treatment equipment, manufacturing tools, etc., can solve the problem that the quenching intergranular precipitation and the refinement of grain size cannot be well controlled, and the impact toughness cannot be improved. The material cannot break through the bottleneck and other problems, and achieve the effect of grain refinement, high impact toughness, and structure improvement

Inactive Publication Date: 2011-04-20
WUXI HONGDA HEAVY IND
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Problems solved by technology

However, with the continuous improvement of use requirements and design requirements, there are higher requirements for the impact toughness of carbon steel tugboat shaft forgings, even higher than the national machinery industry standard JB / T9178.1-1999 "General Technical Conditions for Free Forgings on Hydraulic Presses" "Requirements, conventional quenching and tempering treatment can meet the design requirements of strength and hardness, but it is difficult for higher impact toughness (for large forgings of ordinary carbon steel, impact toughness is a bottleneck)
Conventional quenching and tempering (quenching + high temperature tempering) process, the structure is ferrite structure and pearlite structure, the pearlite structure is the main structure, the structure is relatively uneven, and the existing process cannot better control the crystal formation during the quenching and cooling process. The inter-precipitation and the refinement of the grain size make it impossible to improve the impact toughness, and the material cannot break through the bottleneck

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  • Super-conventional performance heat treatment process for large axial forgings of carbon steel

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Embodiment Construction

[0013] Preferred embodiments of the present invention are described below, and it should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

[0014] The equipment used in this process is as follows:

[0015] (1) Forging heating and heat preservation: 800KW trolley-type resistance furnace;

[0016] (2) Hoisting of forgings: the main hook carries a 32T crane;

[0017] (3) Cooling of forgings: a water tank with a volume of 132 tons and a synthetic quenching liquid tank.

[0018] Such as figure 1 As shown, the heat treatment process of steel shaft forgings, the specific steps are as follows:

[0019] (1) Quenching treatment: heat up to 650°C according to the power, and after 3 hours of heat preservation, heat up to 860±10°C at a speed of ≤80°C / hour, and after 6 hours of uniform temperature, water cooling for 20 minutes and oil cooling for 30 minutes;

[...

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Abstract

The invention discloses a super-conventional heat treatment process for axial forgings of carbon steel in large forgings, comprising the steps of conventional quenching treatment, sub-temperature quenching and tempering. Incomplete austenitizing is adopted in the step of sub-temperature quenching, aiming to reduce intercrystalline precipitates and refined grains. The practical effect shows the aim is achieved. A detail must be paid attention to: the upper limit sub-temperature can not exceed Ac3. The process has the following advantages: obtaining the needed structure preparation through conventional quenching treatment, reducing the intercrystalline precipitates and refined grains through the incomplete austenitizing characteristic of sub-temperature quenching treatment under the premise of ensuring the strength, and improving the structure and the mechanical performance. The process ensures the common carbon steel to break through the bottleneck and obtain higher impact toughness.

Description

technical field [0001] The invention relates to a heat treatment process, in particular to a super-conventional heat treatment process for large carbon steel shaft forgings, belonging to the field of mechanical processing. Background technique [0002] Metal heat treatment is to heat a metal workpiece in a certain medium to a suitable temperature, and keep it at this temperature for a certain period of time, then cool it at a different speed, and control its performance by changing the surface or internal structure of the metal material. kind of craft. [0003] Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processing techniques, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but changes the microstructure inside the workpiece or changes the chemical composition of the surface of the workpiece. , to give or improve the performance of the workpiece. It is characte...

Claims

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Application Information

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IPC IPC(8): C21D9/28
Inventor 邓军
Owner WUXI HONGDA HEAVY IND
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