Manufacturing and inspection method of 34CrNi3MoV valve box forging stock
An inspection method and valve box technology, applied in the field of metal forging, can solve the problems of cumbersome operation process, cracks, complex forming process, etc., and achieve the effect of reducing waste of resources
Pending Publication Date: 2022-01-21
江苏裕隆特种金属材料科技有限公司
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Problems solved by technology
However, in the manufacturing process of the 34CrNi3Mo valve box forging billet, due to the complexity of the forming process and the cumbersome operation process, there will be many factors that lead to cracks, which brings a great risk to whether the forging can finally meet the use requirements.
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[0035] The material 34CrNi3MoV steel ingot is forged by a 30MN hydraulic press to form a valve box forging billet. After quenching and tempering heat treatment of the forging billet, cracks were found on the surface of part of the forging billet. In order to find out the cause of the defect, the defect detection is carried out on the corresponding forging billet. The specific manufacturing and inspection methods are as follows: figure 1 shown.
[0036] 1) Manufacture of valve box forging billet
[0037] According to the work number, the forging production process should be: 13t steel ingot → heating in the furnace (1250°C) → soaking out of the furnace → pressing handle (￠700mm) → chamfering → leaking disc upsetting (H800mm) → 620 flat anvil pull length 20 Forging shape → pressing square (350×550×6700) → trimming (final forging temperature 800°C, forging ratio 6.0:1) → furnace cooling after forging → normalizing heat treatment (air cooling at 910°C) → preliminary exploration o...
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The invention discloses a manufacturing and inspection method of a 34CrNi3MoV valve box forging stock. The manufacturing and inspection method comprises the following steps: (1) forging a valve box; 2) carrying out quenching and tempering heat treatment; 3) carrying out defect inspection; 4) carrying out result analysis: analyzing in combination with macroscopic and microscopic morphology of the fracture. If the fracture surface tends to extend inwards from the fracture source and the fracture area close to the fracture source is decarburized, the crack exists before heat treatment, and the fracture source is combined to judge the generation reason of the crack; if the fracture area is not decarburized, the crack is formed in the heat treatment tempering process. According to the method, strict defect detection is carried out in the forging stock manufacturing process and after machining forming, the generation reasons of the cracks are confirmed step by step, and therefore scientific guidance is provided for manufacturing of the 34CrNi3MoV valve box forging stock.
Description
technical field [0001] The invention relates to a method for manufacturing and inspecting a 34CrNi3MoV valve box forging billet, belonging to the technical field of metal forging. Background technique [0002] 34CrNi3Mo is a high-strength alloy structural steel, which is widely used in the whole forging low-pressure rotor steel of large steam turbines. It has good comprehensive mechanical properties and process properties, and has been widely used in the production of engine rotors and steam turbine impellers. However, in the manufacturing process of 34CrNi3Mo valve box forging billet, due to the complex forming process and cumbersome operation process, many factors will lead to cracks, which will bring great risks to whether the forging can finally meet the use requirements. Therefore, strict defect detection is required during the manufacturing process of the forging billet and after processing and forming to confirm the cause of the crack, so as to adjust and confirm each...
Claims
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Login to View More IPC IPC(8): G01N29/04G01N33/2045
CPCG01N29/04G01N33/2045
Inventor 黄智宋雷钧李祝茂
Owner 江苏裕隆特种金属材料科技有限公司