Answers

• 
  What alternative materials can be used for carbon steel Q195?

  Q195 is a low-carbon structural steel. Finding a suitable alternative depends on the specific application.
  Some common alternative materials are listed below for reference only:
  Q215 has slightly higher strength than Q195, and its applications are largely the same.
  DC01 corresponds to the national standard Q195/Q215, with a tensile strength of 270-410 MPa and a yield strength of 130-260 MPa.
  
  When selecting an alternative material, the most crucial factor is to clearly define the specific application, processing method, and minimum requirements for mechanical properties.
  The carbon and manganese content of alternative materials may differ from that of Q195, which will affect their welding, forming, and other process properties, requiring corresponding adjustments to the manufacturing process.

  
  
• 
  What's the difference between stainless steel bearings and ordinary bearings?

  Bearing steel generally has a higher carbon content to enhance wear resistance, while stainless steel generally has a higher chromium content, exceeding 12%, primarily to utilize its corrosion resistance. Compared to ordinary bearings, stainless steel bearings not only have a significant advantage in material composition but also require much stricter manufacturing processes and precision control.
  The main difference between stainless steel bearings and ordinary bearings lies in their corrosion resistance; other aspects are similar.
  If the operating environment is acidic or corrosive, it is recommended to choose stainless steel bearings, as their service life will definitely be superior to that of ordinary bearings.

  
  
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  What's the difference between a material certificate and a certificate of conformity when purchasing steel. are both necessary?

  When purchasing steel, a material certificate and a certificate of conformity are two different documents, but usually both are required as they are crucial documents for ensuring steel quality.
  The certificate of conformity is relatively simple, mainly containing basic information such as product name, model, specifications, batch number, quantity, and a "qualified" mark. Steel certificates of conformity are sometimes colloquially referred to as quality certificates.
  In addition to basic information, the material certificate details key data such as the steel's chemical composition and mechanical properties (e.g., yield strength, tensile strength). It is an important basis for understanding the steel's performance.
  The material certificate provides detailed performance data for the steel, forming the foundation for quality traceability and technical verification. For export trade, a material certificate conforming to international standards (such as EN 10204) is a core document.