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Introduction to the characteristics of steel castings

Release Date: September 09, 2017

The steel castings have changed or maintained the internal structure of the steel castings in a suitable way, making the materials more plastic and stronger, and meeting the requirements for use under a certain temperature, pressure and environment. This is the need for steel castings. Purpose of heat treatment. Metallographic analysis is a tool for inspecting and analyzing the heat treatment status of castings, helping people understand the internal structure and heat treatment status of steel castings from a micro perspective, so as to achieve the purpose of using steel castings safely.

Relationship between mechanical properties of steel castings and metallographic examination:

1. In general, if the contract does not indicate that the metallographic examination of the cast steel is required, the general mechanical properties of the cast steel shall prevail (i.e. tensile strength, yield strength, elongation, and reduction in area) , Impact performance, hardness), the material manufacturer's metallographic analysis of the valve manufacturer is to monitor the intrinsic quality of the main parts in the valve, to understand the special process technology implementation status, no need to provide the metallurgical inspection report to the valve user, you can keep it for your own archives.

2. In the practice of metallographic analysis of steel castings, if the rating is unqualified (such as a slightly lower grain size), but the mechanical properties of the material are acceptable, as long as the metallurgical level of the material is not clearly specified in the contract, it is customary It still depends on the mechanical performance index. For another example, the high ferrite content in the duplex stainless steel (not exceeding the upper limit) causes coarse grains, but those with acceptable mechanical properties can be accepted without affecting the corrosion resistance.

3. For special operating conditions (anti-sulfur, hydrogenation, high temperature, high pressure, etc.), manufacturers should pay special attention to macro and micro inspection and analysis of materials, such as non-metallic inclusion content, grain size, Intergranular corrosion tendency and phase content in austenitic stainless steels. It must be understood that the microstructure of the material directly affects the performance and service life of mechanical parts. The metallographic analysis of the material is to prevent the "miles of long embankment from falling into a hole". Effective tools.