The roughness standard of seamless steel pipe

The roughness standard of seamless steel pipe

What is the roughness of seamless steel pipes?

The roughness of seamless steel pipes refers to the degree of unevenness on the surface of seamless steel pipes, which is usually evaluated by various technical means such as glossiness, wire drawing marks and surface detection. The roughness of seamless steel pipes is an important factor affecting the surface quality and service life of seamless steel pipes.

The standard of seamless steel pipe roughness

The standard of seamless steel pipe roughness is formulated by the state, industry and enterprises. At present, there are mainly three standards:

1. National standard: The national standard stipulates the two roughness grades of seamless steel pipes, ordinary and precision, and their corresponding detection methods and evaluation rules. Among them, the ordinary roughness grades of seamless steel pipes are Rmax25μm and Rmax12.5μm, respectively, while the precision roughness grades of seamless steel pipes are Rmax6.3μm and Rmax3.2μm, respectively.

2. Industry standard: Industry standards are usually formulated by various industry associations or groups for the guidance of seamless steel pipe production and quality control in the industry. For example, for the interface standards API and international standards ISO commonly used in the petrochemical industry, corresponding seamless steel pipe roughness standards are also stipulated.

3. Enterprise standards: Enterprise standards are usually standards for product quality and technical requirements independently formulated by the enterprise, which can be flexibly formulated according to the actual production situation of the enterprise and customer needs. 

Evaluation indicators of seamless steel pipe roughness

The evaluation indicators of seamless steel pipe roughness mainly include the following aspects:

1.Roughness grade: grade classification formulated according to different roughness standards.

2.Glossiness: Commonly used gloss measurement methods include gloss meter method, microphotometer method, etc., and the gloss value is usually in Ra units. 

3.Wire drawing marks: Wire drawing marks mainly refer to scratches on the surface of seamless steel pipes with roughness standard templates, and are divided into different grades according to the level of the templates. 

4.Surface inspection: including appearance inspection, metallographic structure test, composition analysis test and other aspects, used to find surface defects and determine the quality of seamless steel pipes. 

The impact of seamless steel pipe roughness on quality

The level of seamless steel pipe roughness will directly affect the service life and safety performance of seamless steel pipes. Too high a roughness will make the surface of the seamless steel pipe easy to capture dirt and corrosive media, aggravate the corrosion degree of the seamless steel pipe, and reduce the service life; while too low a roughness will cause lubricating oil leakage and jamming between parts, affecting the safety performance of the seamless steel pipe.

Conclusion

The standards and evaluation indicators of the roughness of seamless steel pipes and their impact on the quality of seamless steel pipes are introduced. The roughness of the surface of seamless steel pipes is an important indicator for measuring the surface quality and service life of seamless steel pipes. The roughness of seamless steel pipes should be strictly controlled and evaluated according to the corresponding standards.

Read more: Seamless Steel Pipe Sizes