1, steel grade, at the beginning of the two figures show that the carbon content of steel, with the average carbon content per few said, such as 40 cr.
2, main alloy element in steel, in addition to the individual microalloy element, usually expressed as a percentage.When the average alloy content < 1.5%, generally only mark symbol in the steel grade, and not indicate content, but in special cases, easy to cause confusion, after the element symbol can be labeled with Numbers "1", such as steel grade "12 crmov" and "12 cr1mov", the former chromium content is 0.4 0.6%, which is 0.9-1.2%, all the rest of the ingredients are the same.When the average alloy element content of 1.5% or higher, or 2.5%, 3.5% or more..., behind the symbol should be marked content, can be said for 2, 3, 4...And so on.For example, 18 cr2ni4wa.
3, in the steel vanadium V, Ti, aluminum, titanium, boron, rare earth and alloy elements such as RE B, micro alloying elements, although the content is very low, still should be in steel grade drawings.20 MNVB steel, for example.Vanadium is 0.07-0.12%, boron is 0.001-0.005%.
4, high quality steel should add "A" at the end of the steel grade, to distinguish it from high quality steel in general.
For special purposes (5, alloy structural steel, steel grade as (or suffix) on behalf of the steel grade USES symbols.Such as riveting screw dedicated 30 crmnsi steels, steel grade is expressed as ML30CrMnSi.
Alloy pipe and seamless tube are both relation and difference, cannot confuse STH with STH else.
Alloy pipe is steel pipe according to the production of materials (i.e., material) to define, as the name suggests is made of alloy pipe;And seamless tube is steel pipe according to the production process (a seam seamless) defined, is different from that of seamless tube is tube, including straight seam welded pipe and spiral tube.
The material of alloy pipe:
16-50 mn, 27 simn, 40 cr, Cr5Mo 12 cr1mov 12 cr1movg 15 crmo 15 crmog 15 crmov 13 crmo44 T91 27 simn 25 crmo 30 crmo 35 crmo 35 crmov 40 to 45 crmo crmo 20 g Cr9Mo 10 crmo910 15 mo3 A335P11. P22. P91. The T91, A106B, kair 102, ST45.8-102.
Weight formula: [] - wall thickness (diameter) * wall thickness * = 0.02466 kg/m (weight of per meter)
Manufacturing process:
1. Hot extrusion (seamless steel tube) : the circular tube billet - heat - punch - three-roll skew rolling, rolling, or pressing - to take off the tube and sizing (or reducing) - cooling - straightening to hydrostatic test or inspection - > tag, put in storage
2. Cold drawing (rolling) seamless steel pipe: the circular tube billet - heat - punch to heading, annealing and pickling to apply oil (copper), multi-channel time cold drawing (cold) and billet tube - heat treatment - straightening to hydrostatic test (NDT) - > tag, put in storage.