First, diesel engine crankshaft forging
(1) Diesel crankshaft forgings are forged by continuous fiber forging. If it is forged by other forging methods such as free forging, it must be submitted to the relevant department for review.
(2) Forgings of diesel engine crankshafts When forging, the ends of the steel ingots should be cut off to avoid the defects of the ingots to ensure the quality of the finished products.
(3) The crank arm of the free forged crankshaft is machined. 5毫米深度的表面层。 The surface of the surface of the forged steel parts after machining, the surface layer of at least 7. 5 mm deep.
(4) The forging ratio of diesel engine crankshaft forgings should meet the following requirements:
a) When forging with steel ingot, the forging ratio of the journal and the crank arm is not less than 3.0, the forging ratio of the flange and other protruding portions is not less than 1.7, and the average cross-sectional area of the steel ingot is used when calculating the forging ratio;
b) When forging with a billet, the forging ratio of the journal and the crank portion is not less than 1.8, and the forging ratio of the flange and other projections is not less than 1.5.
Second, diesel engine crankshaft forging heat treatment
(1) Forgings of diesel engine crankshafts should be subjected to post-forging heat treatment to refine the grains, improve the structure, and prevent white spots.
(2) A crankshaft forging that is forged by a continuous fiber forging method allows heat treatment in a black skin state.
(3) Free forging crankshaft forgings subject to quenching and tempering shall be subjected to mechanical processing (roughing) for final heat treatment.
(4) The final heat treatment method for carbon steel and carbon-manganese steel crankshaft forgings should use one of the following methods, and the tempering temperature should not be lower than 550 ° C.
- tempering ten tempers;
- high temperature normalizing ten normal fires and ten tempers;
- quenching + tempering;
- High temperature normalizing ten quenching + tempering.
(5) The final heat treatment method for alloy steel crankshaft forgings should use one of the following methods, the tempering temperature is not lower than 550 ° C
- quenching ten temper;
- high temperature normalizing ten quenching and ten tempering.
(6) For the crankshaft forgings to be surface hardened, the detailed technical data of the proposed heat treatment process shall be submitted to the relevant department for approval, and the hardness and depth of the hardened layer shall be verified by the test to meet the technical requirements without affecting the crankshaft. The performance of the forging body.
(7) After the final heat treatment of the crankshaft forging, if it is straightened or machined (roughing), tempering to eliminate residual stress is required. The tempering temperature should be at least 30 C to 50 degrees Celsius lower than the tempering temperature of the performance heat treatment.
Third, the surface quality of diesel engine crankshaft forgings
After the roughing of the crankshaft forgings, the magnetic particle inspection shall be carried out, and the quality requirements of the flaw detection shall comply with the provisions of CB 973.
Fourth, the internal quality of diesel engine crankshaft forgings
After the crankshaft forgings are subjected to heat treatment and certain machining (roughing), ultrasonic flaw detection shall be carried out. The quality requirements for flaw detection shall comply with the provisions of CB/T 3907-1999.
Fifth, trimming the defects of crankshaft forgings
(1) Minor defects on the surface of the crankshaft forgings can be eliminated by chiseling or grinding. The removed pockets should be smooth and repaired and should be eliminated after the crankshaft is finished.
(2) Surface defects of crankshaft forgings are not trimmed by the repair welding method.
Sixth, packaging, storage and transportation
(1) For the machining of crankshaft forgings, our company will apply anti-rust agent to the surface of forgings and pack them with anti-rust paper or other packaging materials to prevent corrosion during storage and transportation.
(2) Our company will package the crankshaft forgings and fix them on the brackets to prevent them from being damaged during storage and transportation.
Seventh, diesel engine crankshaft forgings ordering instructions
(1) The purchaser shall specify in the order contract the name, material number, order quantity and delivery status of the forging, the corresponding technical requirements and the inspection items specified by the supplier and the purchaser, and the inspection items other than those required by this standard. 8.2 The buyer shall provide the order drawings and related finishing drawings.
(2) When the demander has special requirements, it shall be negotiated and clearly specified in the order contract.
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