stainless steel welded

stainless steel welded pipe also said, is a curly plate or strip molding made of welded steel pipes after. Welded steel pipe production process simple, high efficiency, different specifications, equipment financing small, but the general strength of less than seamless steel tubes. Since the 1930s, with the production of quality steel rolling and the rapid development of welding and inspection and technological progress, constantly improve the quality of welds, stainless steel welded the growing number of different specifications, and in a growing number of areas instead of Seamless Steel Tube. Welded steel pipes in the form of the weld into Longitudinal Welded Pipe and spiral welded pipe.
stainless steel welded steel plate is used in blank or strip, its welding technology and is divided into different furnace pipe, welding (ERW) and automatic arc of the pipe. Because of their different forms of welding is divided into two Longitudinal Welded Pipe and spiral welded pipe. The end of their round shape is divided into special-shaped pipe and (side, Chen Shui-bian, etc.) pipe. Pipe and its use of different materials and divided into a number of varieties are as follows:
GB/T3091-1993 (low-voltage transmission fluid with galvanized steel pipe welding). stainless steel welded mainly used for transport of water, gas, air, oil and heating hot water or steam, and other generally low pressure of the fluid and other uses. His representative material Q235A grade steel.
GB/T3092-1993 (low-voltage transmission fluid with galvanized steel pipe welding). Mainly used for transport of water, gas, air, oil and heating hot water or steam, and other generally low pressure of the fluid and other uses. His representative for the material: Q235A grade steel.
GB/T14291-1992 (Mine transmission fluid welding pipe). Wind mainly used for mine pressure, drainage, gas-axis with straight seam welded steel pipe. His representative material Q235A, B-class steel. GB/T14980-1994 (low-voltage transmission fluid with large-diameter welded steel pipe). Mainly used for conveying water, sewage, gas, air, steam heating and other low-pressure fluids and other purposes. His representative material Q235A grade steel.
GB/T12770-1991 (mechanical structure with stainless steel welded pipe). Mainly used for machinery, automobiles, bicycles, furniture, decorative Hotels and restaurants and other mechanical components and structural parts. His representative material 0 Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc..
GB/T12771-1991 (transmission fluid with stainless steel welded pipe). Mainly used for transmission of low pressure aggressive media. Representative material for 0 Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc..

Longitudinal Welded Pipe production process simple, high efficiency, low cost, rapid development. The strength of the general spiral welded pipe than Longitudinal Welded Pipe, can narrow the billet production of large diameter pipe, you can also use the same width of the billet production of different diameter pipe. But with the same length of straight pipe joints compared to weld the length of an increase of 30 to 100 percent, and lower production rate.

Therefore, most small-diameter pipe used straight seam welding, large-diameter pipe is mostly used spiral welded

stainless steel welded What is the measurement formula

Thickness formula: δ = P * D / 2 * [σ]
Where δ: units meters;
P: pressure units MPa;
[σ]: Permissible stress units MPa, [σ] = tensile strength / n, n for the safety factor;
P <7MPa time, n = 8; P <17.5MPa when, n = 6;
P> 17.5MPa when, n = 4.

Profile stainless steel
Resistance of air, steam, water and other corrosive media and the weak acid and alkali, salt and other chemical etching medium corrosion of steel. Stainless steel also known as acid. Practical applications, often weak corrosion medium corrosion-resistant steel known as stainless steel, and chemical resistance to corrosion of steel known as the medium of acid. As the two chemical components in the differences, the former does not necessarily corrosion-resistant chemical medium, while the latter generally are of stainless steel. The corrosion resistance of stainless steel depends on the elements contained in the alloy. Chromium is a corrosion resistance to stainless steel was the basic element of chromium in the steel amounted to about 12 percent, chromium and corrosion in the media oxygen role in the formation of a layer of thin steel surface of the oxide film (passive film) , To stop the steel matrix further corrosion. In addition to chrome, there are common elements of the alloy of nickel, molybdenum, titanium, niobium, copper, nitrogen, in order to meet the various uses of stainless steel and performance requirements.
Stainless steel is usually divided into the matrix organization:
1, ferrite stainless steel. Chromium 12 percent to 30 percent. Its corrosion resistance, toughness and weldability with the increase of chromium increase, chloride stress corrosion-resistant than other types of stainless steel.
2, austenitic stainless steel. Chromium-containing more than 18 percent, also contains about 8 percent nickel and a small amount of molybdenum, titanium, nitrogen and other elements. Properties, and corrosion resistant to a variety of media.
3, austenitic - ferrite duplex stainless steel. Both austenitic and ferrite the advantages of stainless steel and have superplastic.
4, martensitic stainless steel. High intensity, but the welding of plastic and poor.
5, precipitation hardening stainless steel. With forming a very good performance and good welding, as a super-strength materials in the nuclear industry, aviation and aerospace industry in the application.
Components can be divided into by the Department of Cr (SUS400), Cr-Ni of the (SUS300), Cr-Mn-Ni (SUS200) and precipitation hardening of the (SUS600).
Second, stainless steel history
60 stainless steel is a development of modern materials

Third, the role of stainless steel
Since the beginning of this century since the invention of stainless steel, stainless steel put the image of modern materials and construction applications reputation of excellence, the envy of its competitors. Stainless steel does not produce corrosion, pitting, corrosion or abrasion. Stainless steel or metal materials used in construction materials in one of the highest intensity. As stainless steel has a good corrosion resistance, so it can permanently maintain the structural components of the project design integrity. Chromium-containing stainless steel also set a high mechanical strength and the extension of the one, the easy parts processing, architects and structural design to meet the needs.

4, grades of stainless steel division
200 - Chrome - nickel - Manganese austenitic stainless steel
300 series - Chrome - nickel austenitic stainless steel
301 - scalability, and for molding products. Or by mechanical processing to the rapid hardening. Welding is good. Abrasion resistance and fatigue strength than 304 stainless steel.
302 - with 304 corrosion resistance, as a result of high carbon content relative to strength better.
303 - by adding a small amount of sulfur and phosphorus to more than 304 cutting.
304 - GM models, namely 18 / 8 stainless steel. GB grades for 0 Cr18Ni9.
309 - better than 304 of the temperature.
316 - Following 304, the second most widely used steel, mainly for the food industry and surgical equipment, add the element molybdenum to obtain a special corrosion-resistant structure. As more than 304 of its anti-chloride corrosion and thus "Marine Steel" to use. SS316 is usually used for nuclear fuel recovery unit. 18/10 grade stainless steel usually meet this application level. [1]
Model 321 - because of the added element of titanium welding materials to reduce the risk of corrosion from other properties similar to 304.
400 series - ferrite and martensitic stainless steel
408 - heat resistance, and weak anti-corrosive, 11 percent of the Cr, 8% of Ni.
409 - the cheapest model (BAR), usually as an automobile exhaust pipe, a ferrite stainless steel (chrome steel).
410 - martensite (high-strength steel chromium), wear resistance, and corrosion resistance poor.
416 - add sulfur to improve the processing of the material.
420 - "cutting tool-class" martensite steel, similar to Brandt's first such high-chromium steel stainless steel. Also used in surgical tools, can do very bright.
430 - ferrite stainless steel, decorative, such as for automotive accessories. Forming a good, but the temperature and corrosion resistance worse.
440 - high-intensity cutting tool steel, carbon slightly higher, after appropriate heat treatment will be higher yield strength, hardness can reach 58 HRC, are among the most hard stainless steel as well. The most common example is the application of "razor-chip." There are three common types: 440 A, 440B, 440C, as well as 440 F (-processing).
500 Series - heat-resistant chromium alloy steel.
600 Series - martensite precipitation hardening stainless steel.
630 - the most commonly used precipitation hardening stainless steel models, usually called 17-4; 17% Cr, 4% Ni.

5, corrosion-resistant stainless steel Why ?

All are metal and oxygen in the atmosphere to respond in the surface oxide film. Unfortunately, in the ordinary carbon steel iron oxide formed on the continued oxidation, corrosion continued to expand, eventually forming holes. Tolerance can use paint or metal oxide (for example, zinc, nickel and chromium), carbon steel plating to ensure the surface, but as people know, this protection is only a film. If the protective layer was destroyed, below the steel began to rust.

Stainless steel corrosion resistance depends on chromium, but because chromium is one of the components of steel, the protection methods vary.

In the amount of chromium reached 10.5 percent, the atmospheric corrosion-resistant steel can significantly increase, but higher chromium content, although still improve corrosion resistance, but was not obvious. Because the use of chromium alloy steel processing, the surface oxide similar to the type of change has become pure metal chromium oxide formed on the surface. This close adhesion of chromium oxide to protect the surface to prevent further oxidation. This extremely thin oxide layer, it can be seen through the surface of the natural gloss, has a unique stainless steel surface. Moreover, if the damage to the surface, which exposed the steel surface and atmospheric response to self-repair, re-create this kind of "passive film," continue to play protective effect.

Therefore, all the stainless steel have a common characteristic, that is, chromium content of 10.5 percent over the.

6, the type of stainless steel

"Stainless Steel" is not just a simple means of stainless steel, but said that more than 100 kinds of industrial stainless steel, stainless steel developed by each in their specific areas of application with good performance. The key to success is to understand first of all use, and then determine the correct steel. On the stainless steel further details can be found by NiDI establishment of "Stainless Steel Guide" floppy disk.

Fortunately, the construction and application of structural steel-related areas are usually only six. They all contain 17 to 22 percent of chromium, better steel contains nickel. Mo added to further improve the atmosphere can be corrosive, particularly resistant to the corrosive atmosphere of chloride.