Steel pipe hardness

Generally, using chemical and electrolysis ways to do pickling processing pipeline anti-corrosion chemical pickling can remove the oxide scale, rust, old coatings, and sometimes used as a sand-blasting after reprocessing.

Although chemical cleaning can reach the surface cleanliness and roughness, the bolt pattern light, and easy to pollute the environment.

Spray radio rust

Seamless tube and pipes

Spray radio rust by high-power seamless steel pipe motor-driven jet (throw) shooting leaves high-speed rotation, making the grit, steel shot, wire, minerals and other abrasive under the centrifugal force on the steel pipe surface spray (throwing ) irradiated, not only can completely remove the rust, oxides and dirt, and the steel abrasive violent shocks and the role of friction, but also to achieve the required uniform roughness. Spray (throwing) radio rust, can not only expand the physical adsorption of the tube surface, and can enhance the mechanical adhesion of the coating with the tube surface. Therefore, spray (throwing) radio rust pipeline corrosion ideal rust ways of. Generally, shot peening (sand) blasting is mainly used for pipe surface treatment, shot blasting (sand) blasting is mainly used for pipe outer surface of the processing. Using spray (throwing) radio rust should pay attention to several issues.

Instrument rust
Using instrument such as wire brush to polish the steel surface to remove loose or the tilt of the oxide scale, rust, welding slag. Rust can reach Sa2 grade manual tools, power tools rust can be achieved Sa3 level, if the steel surface attached to a solid oxide scale, the result is not satisfactory tools rust, amounting to less than anti-corrosion construction requirements anchor pattern depth pickling.

How to detect the hardness of seamless steel pipe, the test methods are divided into non-blank categories, one is the tensile test, one is The hardness test.

The hardness of seamless steel testing to take into account its mechanical properties, which is related to the deformation of stainless steel as raw materials, stamping, cutting and other processing performance and quality. Therefore, all the seamless steel pipe to be tested for mechanical properties.

Tensile test is made of seamless steel pipe sample, the tensile test machine pulled the sample to fracture, and then measure one or several mechanical properties, usually only the determination of tensile strength, yield strength, elongation after fracture and rate of reduction in area. Tensile test is the most basic mechanical properties of metallic materials test methods, almost all of the metal materials, as long as the mechanical properties have required, are provided for tensile test. Especially those whose shape is not convenient for hardness testing, tensile testing becomes the only measure of mechanical properties.

Hardness test is a hard head with a hardness tester pressed into the surface of the specimen under specified conditions, and then test the indentation depth or size, in order to determine the size of the material hardness. Hardness test is the simplest, fastest and easiest to implement method in mechanical testing of materials. Hardness tests are non-destructive with approximate scaling between material hardness values and tensile strength values. Material hardness value can be converted into tensile strength value, which has great practical significance.

Since tensile testing is not convenient for testing and is easily scaled from hardness to strength, there is an increasing tendency for people to test only material hardness and less to test their strength. Especially due to the continuous improvement and innovation of the durometer manufacturing technology, some materials that could not be directly tested for hardness, such as seamless steel pipe, seamless steel plate and seamless steel strip, may now be able to directly test the hardness. Therefore, there is a tendency that the hardness test gradually replaces the tensile test.

Most of the national standards for seamless steel materials both provide tensile testing and hardness testing. For those who do not facilitate the hardness test materials, such as seamless steel pipe only provides tensile test. In the seamless steel standard, the general provisions of the cloth, Luo, Victoria three kinds of hardness test methods, determination of HB, HRB (or HRC) and HV hardness values, provides only one of the three hardness values can be measured. In particular, the latest portable rockwell hardness tester, rockwell hardness pipe, can be as thin as 0.05mm seamless steel plate, seamless steel pipe and as thin as ¢ 4.8mm seamless steel pipe for rapid and accurate hardness testing, Making the problems that were difficult to solve in the country solved in the past.

Seamless pipe Specification, standard and identification

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.