Stainless steel pipe jointWhere is the classification difference

As we all know, stainless steel pipe has a strong ability of atmospheric oxidation and is not easy to rust under normal circumstances, & ldquo; Stainless steel pipe & rdquo; Hence the name of. But what I want to tell you today is that stainless steel pipes will also rust. I believe many friends will be surprised! I believe there are many people who don't know how to explain to customers! Next, let's popularize science!

The compressive strength of duplex stainless steel alloy is twice that of austenitic stainless steel. Compared with L and 317L, the designer can reduce its weight. Alloy is especially suitable for & mdash; 50° F/+600° F temperature range, in strict cases (especially for welded structures), such as salt, sweat stains seawater, soil sea breeze, etc. stainless steel corrodes rapidly in the presence of chloride ions, even surpassing ordinary low-carbon steel. Chloride ions form complexes with Fe in alloy elements, reducing the positive potential of Fe, and then being stripped of electrons and oxidized [1].

At low temperature, the quality of professional stainless steel plate, coil, strip and tube is guaranteed. The company is professional, timely and cost-effective. It has become the first choice brand for many wire products. Welcome to buy! Ferritic stainless steel tubes have low-temperature brittleness like carbon steel, while austenitic steel does not. Therefore, ferritic or martensitic stainless steels have low-temperature brittleness Austenitic stainless steel or nickel base alloy does not show low temperature brittleness. Sus410 (13Cr) SUS430 of ferritic stainless steel pipe (18cr) and others show a sharp drop in impact value at low temperature. Therefore, it is necessary to pay special attention when using at low temperature. As a way to improve the impact toughness of ferritic series stainless steel, high purification process can be considered. With the help of grade C and N, when the embrittlement temperature is improved in the range of - 50 ℃ to - 100 ℃, it is possible to use it in freezing related projects Sus430lx (18cr Ti, Nb LC) and sus436l (18cr Mo Ti, Nb LC) have been applied to frozen shells. Ferritic stainless steel has a body centered cubic structure. When the material properties become weak, sharp cracks will expand rapidly and cause brittleness. Austenitic stainless steel will not produce brittleness because it has a face centered cubic structure. Austrian stainless steel SUSL (18cr-9ni LC) is used And SUSL (18cr-12ni-2mo-lc) show that they still have superior impact characteristics at low temperature. However, pay attention to the precipitation of ferrite or martensite due to processing, and the tendency of embrittlement due to sensitization and carbide or & sigma; equal heterogeneous precipitation.

.　　309— It has better temperature resistance.

Manufacturing process hot rolling (seamless steel pipe): round tube blank → Heating → Perforation & rarr; Three roll cross rolling, continuous rolling or → Off pipe & rarr; Sizing (or reducing) → Cooling → Straightening & rarr; Hydrostatic test (or flaw detection) → Mark & rarr; The raw material for warehousing and rolling seamless pipe is round pipe blank. The round pipe blank shall be cut and processed by cutting machine, and the blank with a growth of about 1m shall be brought to the furnace for heating. The billet is sent to the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature in the furnace is the key problem. After the round tube billet is discharged from the furnace, it should be pierced through the pressure piercer. Generally, the more common piercer is the cone roll piercer. This piercer has high production efficiency and good product quality. It is specialized in stainless steel plate, stainless steel coil, good waterproof performance, fire and high temperature resistance, strong overload capacity, corrosion resistance, radiation protection, long service life large perforation diameter expansion, and can wear a variety of steel grades. After perforation, the round tube blank is successively rolled by three roll cross rolling, continuous rolling or rolling. Take off the pipe after sizing. The conical drill bit of the sizing machine rotates into the steel embryo at high speed to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine bit. After sizing, the steel pipe enters the cooling tower for water spray cooling. After cooling, the steel pipe will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydrostatic test) for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected. Steel pipes should be strictly selected manually after quality inspection. After the steel pipe is inspected,316L thick wall stainless steel pipe, the number, specification, etc. shall be sprayed with paint. And hoisted into the warehouse by crane.

Windproof and ventilation. Where there is wind, please take measures to block the net, and take appropriate ventilation measures indoors.

Check whether the sealing ring of pipe fittings is complete and clean and whether the placement position is correct. If there is dirt,0.5mm304 stainless steel plate, it must be cleaned up. If the sealing ring is damaged, it must be replaced again.

Stainless steel pipe packing bag is nothing more than the function of protecting the surface of stainless steel pipe, so most stainless steel pipe users do not have to question this point.

Let PS be the external force at the yield point s and fo be the cross-sectional area of the sample, then the yield point & sigma; S = PS / fo (MPA), MPa is called MPa, equal to n (Newton) / mm (MPA = 106pa, PA: Pascal = n / M

Highly recommended.201 series & mdash; Chromium nickel manganese austenitic stainless steel.

The inventory of stainless steel pipes may be an important factor in market conditions. This is because at this stage, steel inventory has become an important index to investigate and judge the situation of stainless steel pipeline shopping malls, and has become a wind vane to judge the future market trend. What was the stock of stainless steel tubes at that time? It directly affects the air of shopping malls, and then distributes the business behavior of participants in shopping malls

After hot rolling, it is subject to heat treatment and pickling treatment.

　　430— Ferritic stainless steel for decoration, such as automotive accessories. Good formability, but poor temperature resistance and corrosion resistance.

safety requirements .Under plasma arc cutting corrosion conditions, there are dust containing other metal elements or attachments of dissimilar metal particles on the surface of stainless steel. In the air, which causes electrochemical reaction and the protective film is affected, which is called electrochemical corrosion.

CE-8-90“ Code for design of cold formed stainless steel structural parts & rdquo; And & ldquo; jointly published by nidi and euro inox; Structural stainless steel design manual & rdquo; The design of structural parts for buildings with long service life and good integrity has been simplified.

Process performance inspection: flattening test, tensile test, impact test, flaring test, hardness test metallographic test, bending test and nondestructive testing (including eddy current testing, X-ray testing and ultrasonic testing).

.　　SPHCSPHC—& mdash; In the first place, s is the abbreviation of steel, h is the abbreviation of hot heat, and C is the abbreviation of commercial. It generally represents hot-rolled steel plate and strip.

Stainless steel has the ability of atmospheric oxidation, that is, it does not rust. At the same time, it also has the ability of corrosion resistance in the medium containing acid, alkali and salt, that is, corrosion resistance. However, its corrosion resistance changes with its own chemical composition, mutual state,Stainless steel seamless steel pipe, service conditions and environmental medium type. For example, 304 has absolutely excellent corrosion resistance in dry and clean atmosphere, but it is moved to In coastal areas, in the sea fog with a lot of salt, it will soon rust, while 316 stainless steel performs well. Therefore, not any kind of stainless steel can resist corrosion and rust at any time

Low temperature embrittlement --- in low temperature environment, the deformation energy is small. In the low temperature environment, the phenomenon that the elongation and area shrinkage decrease is called low temperature embrittlement. Most of them are produced on the body centered cubic structure of ferrite series.