How does a forging factory ensure the quality of forgings?

2024-08-14 15:30:46

Forging inspection has sampling properties. If the sampling is qualified, it indicates that the entire acceptance forging is qualified. Secondly, the inspection items vary depending on the type of forging.

How to ensure the quality of forgings and make sampling inspections representative? This requires corresponding measures to be coordinated in forging technology standards, production processes, and technical management systems. Different factories may not be exactly the same, but they are roughly as follows.

1、 Raw material re inspection system

According to the technical standards for shaft forgings, raw materials need to be re inspected according to the melting furnace number before they can be put into production; Raw materials undergo head management and ultrasonic inspection. The so-called head management refers to the special marking that needs to be placed on one end of the raw material steel ingot riser. During material retesting, samples are taken from the riser end for inspection. If the raw materials at the riser end pass the inspection, the quality of the remaining parts is generally not a problem.

Ultrasonic inspection refers to the step-by-step ultrasonic testing of raw materials to detect internal metallurgical defects and ensure that the quality of the raw materials produced meets the standards. Exposing metallurgical defects before production is not only economical, but also simpler and more accurate compared to non-destructive testing on forgings.

2、 Forging Forming and Modification System

The shaft forging process can only be put into mass production after being finalized. The forging process is the forging process specification, which refers to the entire process of raw materials from cutting, forging, heat treatment, to cutting and processing of forgings. When shaping, there are more inspection items for forgings than in the table above, including sampling from different parts and directions, as well as quality items that may be affected by forging processes. For important and complex shaped forgings, they need to undergo trial processing and product use before the process can be finalized.

Ensure the stability of the molding process and do not make arbitrary changes. After the process is finalized, it must be strictly implemented, and any changes must be approved through research. When the forging is transferred to another factory for production or the dominant process is changed, it should be re evaluated and finalized according to the situation. In order to improve the process, accumulate experience, and verify the stability of the forging process, specialized inspections for processability can be conducted. Generally, it is carried out regularly or once after producing a certain quantity of forgings. The test items, sampling locations, and quantities for process specific inspections are more than those specified for normal inspections.

3、 Reasonably group batches in production

The acceptance of each batch of shaft forgings should consist of forgings with the same drawing number, melting furnace number, and production batch number. The forgings supplied in the final heat treatment state should also consist of forgings from the same heat treatment furnace. Abbreviated as "San Tong" and "Si Tong". This batch is determined based on factors that affect the quality of forgings.

Therefore, for the same drawing number, there is the same forging process; The same smelting furnace number has the same smelting foundation and sensitivity to forging processes; If the same production batch number and the same heat treatment furnace are used, there will be the same forging and heat treatment conditions. This type of grouping is reasonable and also the strictest. In actual production, starting from the stability of material quality and forging quality, the type of forgings, and the convenience of production, while ensuring the quality of forgings and representative sampling, it is allowed to appropriately relax the batch conditions.