Related standards for quality grading of forgings

Quality grading of forgings is very important, and it is also an important method to promote and improve the quality of forgings. In 1987 promulgated in the Commission of enterprises 19 special 02 "Machinery industry national enterprise level standards" has provisions. The regulations point out that forgings are divided into first-class products and qualified products, and the proportion of first-class products in the total output value of the corresponding grade enterprises has been stipulated.

Therefore, understand the forging grade standard, master the forging grade method and assessment content, is very important, more helpful to further improve the quality of forging, so the following to sort out the following several forging grade related standards, for reference only.

First, forging grade related standards

1. Steel free forging qualified products

The internal quality and appearance quality of the forgings are up to JB4385-87 "General Technical Conditions for Free forgings on Hammer" and meet the contract requirements.

The main outline dimensions of the forgings reach JB4249-1986 "Machining Allowance and Tolerance of Steel Free Forgings on Hammer".

2. First class steel free forging

The internal quality and appearance quality meet the requirements of JM4385-87 "General Technical Conditions for Free Forging on Hammer".

The main dimensions of the shape meet the requirements of DIN7527 "Processing Allowance and Allowable Deviation of Steel Free forgings" (German standard).

3. Qualified steel die forgings

The structure design conforms to JB/Z295-87 "Die forging process structure Elements".

The internal quality and appearance quality meet JB3835-1985, "General Technical Conditions for Steel Die Forging" and meet the contract requirements.

The main dimensions of the appearance meet the requirements of JB3834-1985, "Steel Die Forging Tolerance and Machining Allowance".

4. Steel die forging first class

The structure design conforms to JB/Z295-87 "Die forging process structure Elements".

The appearance quality of forgings conforms to German standard DIN7526-69.

The internal quality conforms to JB3835-1985, "General Technical Conditions for Steel Die Forging" and meets the contract requirements.

The appearance and dimension accuracy of the forgings conforms to DIN7526.

Two, detection, test method

Forgings structure design, appearance quality and dimensions are tested with conventional measuring tools or samples; The die forgings and complex forgings are detected by the marking platform; Surface defects can be observed by naked eye or detected by conventional surface defects such as pickling and magnetic powder as required.

The quality and intrinsic quality of raw materials can be tested by chemical analysis, hardness test, low magnification test, fracture test, mechanical property test, impact test and metallographic test as required by the contract.

Three, forging grade determination method

1. Quantity of sampling and sealing samples

Free forgings on the hammer shall be sampled at the production site according to the supply status. The quantity shall not be less than 10 pieces.

The NUMBER OF SAMPLING VARIETIES OF DIE FORgINGS DEPENDS ON THE production site and inventory situation, but not less than 5 varieties, EACH variety OF samples not less than 5 pieces.

2. Determination of quality grade of forging samples

The sample forgings are tested and counted item by item according to the contract requirements and test methods, and the quality grade is determined according to the total qualified rate after calculating the total qualified rate.

3. For die forgings with inherent quality requirements, samples can be cut from the sampled forgings, and the test results shall meet the acceptance standards or technical agreements stipulated in the contract.

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