304 stainless steel pipeBrief analysis of the advantages and disadvantages

announcer:hp717HP127443542 release time:2021-10-30 23:10:58

4: stainless steel strip (stainless steel coil): or coil, coil, coil, plate coil. There are many names, 201 stainless steel pipe stainless steel pipe, all metals react with oxygen in the atmosphere to form an oxide film on the surface. Unfortunately, expanding the corrosion and finally forming holes. The carbon steel surface can be guaranteed by electroplating with paint or oxidation resistant metals (e.g. zinc, nickel and chromium), but as is known, this protection is only a thin film. If the protective layer is, and the products involved in this case belong to the medium and high-end products of stainless steel pipe. According to incomplete statistics, in 2010, China exported about 20000 tons of stainless steel pipes to the EU, accounting for about 13% of the total exports of stainless steel pipes that year.

.High pressure water jet cutting (professional water cutting: Shanghai Xinwei)

The internal and external greasy dirt and sundries at the pipe end shall be completely removed to keep the pipe inside the pipe fittings clean.

Relevant information stainless steel export is an important part of China's export economy. It plays an important role in stimulating China's economic growth. However, from the current situation of China's stainless steel foreign trade, China's stainless steel export has encountered great resistance.


304 stainless steel pipeBrief analysis of the advantages and disadvantages



5 identification number and indication use international chemical element symbols and national symbols to indicate chemical composition. For a long time, stainless steel plate, stainless steel coil, stainless steel belt and stainless steel pipe have complete products, excellent quality and favorable price. Use letters to indicate composition content: for example, China and Russia use fixed digits to indicate steel series or numbers; for example, the United States, Japan, 300 series, 400 series 200 series; the serial number is composed of Latin letters and order, which only indicates the purpose.

In engineering, the following methods are often used to prevent intergranular corrosion: reduce the amount of carbon in steel so that the amount of carbon in steel is lower than the saturated solubility of austenite in equilibrium that is, fundamentally solve the problem of precipitation of chromium carbide (cr23c) on the grain boundary. Generally, the requirement of intergranular corrosion resistance can be met when the amount of carbon in steel is reduced to less than 0.03%.

Remarks: to ensure the nickel content of stainless steel strip and the mechanical properties of stainless steel strip, material certificate (Baogang material), Japan Nippon Steel Material Certificate (Nippon Steel material), SGS report etc. can be provided.

Product line.Stainless steel pipe is a long strip of steel with hollow section and no joints around it. The thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, the higher its processing cost will be.

In the grades of Japanese steel (JIS Series), ordinary structural steel is mainly composed of three parts, which represent the material such as s (steel) represents steel and f (ferrum) represents iron; The second part represents different shapes, types and uses, t (tube) represents tube, and K (kogu) represents tool; The third part represents the characteristic number, which is generally low tensile strength. For example: SS400 & mdash& mdash; One s represents steel, and the second s represents & ldquo; Structure & rdquo; (structure), 400 is the lower limit tensile strength of 400MPa, and the whole represents ordinary structural steel with tensile strength of 400MPa.

Ti-5a alloy with improved titanium and overall corrosion resistance has been used to manufacture u and Pu solution evaporation boilers and heat recovery evaporation boilers in Donghai reprocessing plant, Japan. In addition, because zirconium has stable corrosion resistance in the environment, Aomori County, Japan. The US Academy's ruling that the countervailing duty is not suitable for products from non market economy countries has just given China's steel pipe enterprises a little relief. The anti-dumping stick from the EU has given a heavy blow to hundreds of domestic stainless steel pipe manufacturers.


304 stainless steel pipeBrief analysis of the advantages and disadvantages



Stainless steel pipe national standard thickness in the stainless steel pipe industry, the steel that meets the national standard is generally called & ldquo; National Standard & rdquo; Inferior steel that does not meet national standards is called & ldquo; Winning the bid& ldquo; Non standard & rdquo; In practical application, the quality of national standard and non-standard is similar, mainly due to the difference in thickness. A thickness of national standard is actually 1mm, but a thickness of non-standard is actually only 0.8mm or other thickness less than 1mm. Non-standard is basically equivalent to winning the bid. Standard index size (323mm) label number standard implementation standard gbt14976-2012 non-standard specific thickness ratio outer diameter steel pipes are produced according to the standard. 2 non-standard belongs to customized difference. Wood office says ha ha customized on demand. 3 thickness area: the difference between standard, thickened, stainless steel American Standard and national standard mainly lies in C content and P content; The C content and P content of Chinese standards are lower than those of American Standard ASTM A312@_@ The two important elements of material are chromium and nickel, 15 9 large plants and 18 8 large plants of national standard and 18 8 small plants of American Standard 132@_ @ The national standard contains more than 17 chromium and the American Standard contains more than 18 chromium@_@ Stainless steel pipe is an American Standard, not in the national standard. The corresponding national standard is 06cr19ni10.

production costs.  303— Add a small amount of sulfur and phosphorus to make it easier to cut.

Continuous casting shall be adopted for stainless steel pipe fittings, so as to improve the comprehensive yield, and cooperate with out of furnace refining, which significantly improves the production efficiency, omits the blank opening process and saves a lot of energy consumption.

Han Jianbiao, an analyst at Zoomlion steel, pointed out that since, China's steel pipe exports have been only 30000 or 40000 tons per month, of which seamless pipe exports are only about 10000 tons per month.

.Stainless steel pipe will rust? It will rust. The stainless steel pipe only means that it is not easy to rust, which does not mean that it will not rust. If it is placed in seawater, it will still be embroidered soon. It will not rust at room temperature. If it is in a high sulfate alkali environment for a long time, it will produce spot rust. It will not rust under normal circumstances, except in places with acid rain. Stainless steel pipe itself

The resistance, linear coefficient, thermal conductivity, quality, hot melt and magnetism of stainless steel pipe will change greatly at low temperature. Resistance, line coefficient decreases at low temperature; The thermal conductivity and mass heat capacity decrease sharply at low temperature; Young's modulus (longitudinal modulus) increases when the temperature decreases. Because the austenitic series stainless steel pipe has MS point (martensite start temperature or martensite formation temperature) at low temperature (subzreo temperature), martensite can be formed when it is kept below MS point. The formation of martensite at low temperature makes the representative steel sus (18Cr-8Ni) of austenitic stainless steel non-magnetic at room temperature and magnetic at low temperature.

It has lower linear coefficient than austenitic stainless steel and is close to carbon steel. It is suitable for connection with carbon steel and has important engineering significance, such as the production of composite plate or lining.