标签归档：pipe fitting suppliers

a href=http://www.steel-pipe-fittings.net/stainless-steel-elbow/ target=_newimg src=http://www.steel-pipe-fittings.net/upfiles/-Bend-ElbowBend-Elbow-main.jpg border=0 title=stainless steel elbow //abrdiv style=BACKGROUND: #fbf0fa;span style=FLOAT: right;font-size:10px;Web Design And Seo For www.china-webdesign.com/spandiv style=FONT-SIZE: 16px;a href=http://www.steel-pipe-fittings.net/stainless-steel-elbow/ target=_blankstainless steel elbow/a – China Manufacturer/divdiv style=line-hight: 8px; FONT-SIZE: 12px;Thank you for inquiry my stainless steel elbow, Tel:+86-577-85989898, Email:JD@CNJIEDE.CN/divdiv style=COLOR: #0e774a; FONT-SIZE: 12px;http://www.steel-pipe-fittings.net/stainless-steel-elbow//div/divbrbrpBeijing North High Valve Factory is a research, development, production and sales of specialized new companies in the same industry at home and abroad have a significant dominance. Leadership in advanced management concepts in business management, quality management, as is always the first goal to be pursued, and has excellent production equipment, strong technical force, advanced detection methods, with robust talent management system and after-sales service, and passed the ISO9001 : 2000 international quality system certifications./p
pnbsp;nbsp;nbsp; To meet the market trends, now with the Beijing valve plant, Tanggu valve plant together, through the introduction of capital and technology, so that the factory in the production level, scale and management both in terms of a new field. Has now established a manual worm gear, electric, pneumatic, corrosion, metal seal and high, medium and low pressure valve products, which are widely used in water supply, drainage, oil, chemical, smelting, power plants, pharmaceutical, food and high-rise buildings, etc. ./p
pnbsp;nbsp;nbsp; Pipe Group is located in St. Day quot;Hometown of China pipe fittingsquot; – Mengcun. Butterfly doors are with Beijing Beijing factory specialized production and sales joint national standard, elbow, flange, tee, size, head, middle, eccentric, PTFE, electric, signal series butterfly valve, butterfly valve, check valve soft joints, bellows, and all kinds of brass valves. Adhering to the cooperation and win-win business ideas, from north to flee abroad valve products, the industry s influence is increasingly prominent./p
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a href=http://www.steel-pipe-fittings.net/stainless-steel-elbow/ target=_newimg src=http://www.steel-pipe-fittings.net/upfiles/-Bend-ElbowBend-Elbow-main.jpg border=0 title=stainless steel elbow //abrdiv style=BACKGROUND: #fbf0fa;span style=FLOAT: right;font-size:10px;Web Design And Seo For www.china-webdesign.com/spandiv style=FONT-SIZE: 16px;a href=http://www.steel-pipe-fittings.net/stainless-steel-elbow/ target=_blankstainless steel elbow/a – China Manufacturer/divdiv style=line-hight: 8px; FONT-SIZE: 12px;Thank you for inquiry my stainless steel elbow, Tel:+86-577-85989898, Email:JD@CNJIEDE.CN/divdiv style=COLOR: #0e774a; FONT-SIZE: 12px;http://www.steel-pipe-fittings.net/stainless-steel-elbow//div/divbrbrpInvestment casting is the final product as copies, the paraffin-like material pressed into precise smooth wax, the wax coating on the refractory layers, drying the slurry to be formed after shell hardening, and then solidified in the shell-type melt the wax mold to make out, then make solid shell roasting, drying, and finally then pouring molten liquid metal into the shell, the shell of liquid metal in the cooling, freezing after a smooth precision castings. This casting process can produce sophisticated, close to the final shape of the product, process, or very little time to process the metal parts can be used directly or fine arts and crafts, so it is a liquid near net shape metal forming processes. Compared with the sand casting method, with the following characteristics:/p
pnbsp;nbsp;nbsp; 1 casting dimensional accuracy, surface roughness is low, you can achieve little or no machining process;/p
pnbsp;nbsp;nbsp; 2 can be cast very light weight thin-walled parts or castings; particularly suitable for casting with a pattern, text or trench type casting;/p
pnbsp;nbsp;nbsp; 3 can be particularly complex castings foundry, or a combination of many parts, welding./p
pnbsp;nbsp;nbsp; China is the birthplace of investment casting technology one. According to research, in the Spring and Autumn Period dating back 2,500 years ago there was already a lost wax casting. Suizhou in Hubei in 1978, unearthed the statue and the tomb plate is lost wax casting early masterpiece. Modern investment casting process is the formation of the early 20th century. During World War II, the defense, aerospace development, the United States, Britain and other countries using the first method of investment casting production jet engine turbine blades. Since the 1980s, around the world casting production, value, quality, and has great growth and improve the current precision casting a positive, large, complex, components in the direction of the entire cast./p
pnbsp;nbsp;nbsp; China s investment casting in the 1950s began to be used in industrial production, first from the aerospace sector and gradually developed into all industrial sectors, has been widely used./p
pnbsp;nbsp;nbsp; Mainland China casting industry development/p
pnbsp;nbsp;nbsp; 1 precision casting industry in China the size of/p
pnbsp;nbsp;nbsp; Although the casting industry in China in the mid-1950s has been established, and gradually promote the application, but the rapid development really is in the early 1990s, ten years since, especially in recent years. At present, China has two levels of investment casting process, the first class enterprise, medium-temperature mold materials and molding silica or ethyl silicate binder system shell investment casting process, that is internationally accepted investment casting process . The second category is the use of low modulus material and sodium silicate binder system shell process, the casting dimensional accuracy and surface roughness worse than the first, reach the level of international investment casting. According to the mainland, it is still used in the mold temperature or low temperature molding material, the surface layer silica sol, water glass reinforcement system shell layer composite technology, can ensure high dimensional accuracy and surface quality of lower costs. According to statistics, in 2001 the first class manufacturers use more than 350, the annual output 75,000 tons, annual output value of 3.28 billion yuan; second process manufacturers (including composite process) over 1350, annual output of nearly 20 million tons, value of 1.5 billion. 2002, production reached 321,000 tons more, the output value reached 5.49 billion yuan. Production in 2002 was 6.4 times in 1988. The output is 330 million in 1988 to 16.6 times./p
pnbsp;nbsp;nbsp; (2) the level of technology, casting quality and product categories to see from the level of use and quality/p
pnbsp;nbsp;nbsp; At present, China Precision Casting production of castings are mainly: the use of first class gas turbine technology and the production of castings for air quality reached the international level, there are 50 manufacturers, the annual output 5000 tons, annual output value of 400 million yuan; using the first and complex process of commercial production of precision castings, and its quality is lower than the standard inspection items and aviation parts, there are 300 or so, the annual output 70,000 tons, annual output value of 2.88 billion yuan; production process using the second category of dimensional accuracy and surface roughness requires low investment casting casting blank pieces, there are 1350 or so, the annual output of nearly 20 million tons, annual output value of 1.5 billion. Castings from three quality levels of the weight distribution can be seen, high levels of air casting yield little, only 1.8% of total general commercial casting 25.6%, and the quality not up to international standards, water glass casting accounted for 72.6% of total production. General and the United States, Britain, Europe and Japan and other advanced countries and regions castings compared to the market structure, there is a clear gap between the proportion of high-quality casting is still very low./p
pnbsp;nbsp;nbsp; Nevertheless, China investment casting process in all aspects, or has made substantial progress, casting a greater impact on the development of new materials, new processes, new equipment, there are many, such as water-soluble core, ceramic core, metal improvements, large-scale investment casting technology, titanium investment casting, directional solidification and single crystal casting, filtering, hot isostatic pressing, rapid prototyping, computer applications, and casting in the development of mechanization and automation technologies to make casting can not only produce small castings, and can produce large castings, the largest size of the outline of Castings nearly 2m, while the minimum wall thickness less than 2mm. At the same time has become more sophisticated castings, in addition to linear tolerances, the parts can achieve high geometric tolerances. Casting surface roughness values ??are also more can be achieved Ra0.4um./p
pnbsp;nbsp;nbsp; 3 matching business gradually complete/p
pnbsp;nbsp;nbsp; As the casting industry, the rapid development of the relevant supporting business led to rapid development. Mainly in the mold processing, equipment manufacturing, raw material production. According to preliminary statistics, the manufacture of processing equipment based professional casting mold factory, casting factory has been concentrated in areas such as Guangdong, Shandong and Wuhan formation, specialized equipment manufacturers everywhere; casting raw material production and suppliers has grown to nearly a hundred, and because first casting mold material needed for the production process, zircon powder, belt and other accessories, and some advanced equipment not yet produced domestically, imported from abroad each year the number of with tons of raw and auxiliary materials. However, due to the conditions of China s basic industries and resources compared with other developing countries, much better, so casting service development, will be extended to Southeast Asian countries and the world and develop their markets./p
p4 industry and the gap between international standards and the advantages and compared to the level of international investment casting/p
pnbsp;nbsp;nbsp; Casting industry in China, the application process to produce first class air casting low production, high-quality precision castings are not many, most of the production of less precision pipe fittings, hardware, harness and auto parts, alloy single species, especially the high-temperature alloys and non-ferrous alloys small proportion of China s casting level is still very backward./p
pnbsp;nbsp;nbsp; However, China s low labor costs, raw materials rich in prices of the products account for a large advantage, as long as product quality, there is still great in the international competitiveness. Meanwhile, the rise of the domestic high-tech industry, mechanical industry, the precision, miniaturization, and the construction industry have been put forward some of the regulations and local laws and regulations, and stainless steel castings with bronze instead of cast iron pipe fittings, casting industry for the unprecedented business opportunities./p
pnbsp;nbsp;nbsp; Meanwhile, China s private sector to join the casting and rapid development, China casting industry has injected fresh vitality, has become a national casting industry s most powerful, most realistic competitors. Such enterprises from the 1980s to the early 1990s, mostly in the form of joint ventures and wholly-owned, from Taiwan, Japan, the introduction of the system silica shell craft materials, mainly in coastal areas and the surrounding areas, the majority of its products sold in international markets, but also because of its advanced systems, flexible, efficient management, so the efficiency is very good. Although only 20 years of development, but the casting industry in China has become a commitment to force the export business. On the other hand, because of its high level of equipment and facilities, processes and quality standards in the country an advanced level, basically meeting the general level of foreign, direct export orders and market alliances, product value remained at a high level, the basic international standards. Or from both the technical level in terms of marketing channels, they are state-owned enterprises casting strong competitors. The Precision Casting Co., Ltd., Dongfeng to manufacturers, represented part of the second and third class technology companies in recent years, regardless of technology level, product quality and labor productivity, advance to the international market is accelerating and will continue to raise the level of Chinese casting industry positive efforts./p
pnbsp;nbsp;nbsp; In recent years, steel castings for low temperatures increased, many of which are low temperature pressure parts, casting most of these low-temperature impact toughness, there are strict requirements./p
pnbsp;nbsp;nbsp; In all the requirements of steel castings in steel plants for many terms, is the most difficult compliance impact toughness. Usually taken to improve the impact toughness of measures no more than the following:/p
pnbsp;nbsp;nbsp; ◆ reduce the carbon content;/p
pnbsp;nbsp;nbsp; ◆ an appropriate increase in manganese-carbon ratio (Mn / c);/p
pnbsp;nbsp;nbsp; ◆ adding alloying elements such as Ni, Cr, Mo, etc.;/p
pnbsp;nbsp;nbsp; ◆ reduce the sulfur content;/p
pnbsp;nbsp;nbsp; ◆ reduce sulfur in steel than in mixed material to improve the form of sulfide inclusions;/p
pnbsp;nbsp;nbsp; ◆ the use of refining processes;/p
pnbsp;nbsp;nbsp; ◆ improved heat treatment/p
pnbsp;nbsp;nbsp; The above measures, the improvement of heat treatment is the preferred solution should be valued, because:/p
pnbsp;nbsp;nbsp; ◆ casting process does not lead to significant adjustments;/p
pnbsp;nbsp;nbsp; ◆ do not have to add equipment;/p
pnbsp;nbsp;nbsp; ◆ little increase in production costs./p
pnbsp;nbsp;nbsp; In 1978, EGNisbett, RDASP and DEMorgan, who published a two-phase region of forged carbon steel for heat treatment study. Nuclear power plants with carbon steel forging, heat treatment by the two-phase region, the impact toughness increased about twice the tensile strength only slightly./p
pnbsp;nbsp;nbsp; Since then, Canada s steel industry and steel enterprises in Europe some of the heat treatment of the two-phase region studied, and satisfactory results./p
pnbsp;nbsp;nbsp; 1 What is the two-phase heat treatment area/p
pnbsp;nbsp;nbsp; The two-phase zone casting heat treatment, is in the casting of the original implementation on the basis of normalizing or quenching, coupled with the heat only to the two-phase region to the second normalizing or quenching./p
pnbsp;nbsp;nbsp; Two-phase zone between the A1 and A3 steel in this range are not fully austenitic, organized by the alpha; plus gamma; two-phase composition, so called two-phase region. No two-phase eutectoid steel area, so this deal only applies to sub-eutectoid steel. Carbon steel, the lower range of its two-phase region of the more wide./p
pnbsp;nbsp;nbsp; Microstructure of ferrite plus pearlite for the sub-eutectoid steel, heated to a temperature above the A1, the phase change of the organization as follows:/p
pnbsp;nbsp;nbsp; a. just over A1 (727 ℃)/p
pnbsp;nbsp;nbsp; Remained essentially unchanged ferrite, pearlite and gradually transformed into austenite. The new group of austenite grain boundaries in pearlite nucleation, pearlite in a thick sheet of carbon and become spherical. As the transition progresses, the carbon to continue to grow from the spherical carbon diffusion in austenite. Thus, in the original ball of light in vivo formation of new ferrite grains. Pearlite transformation time this happens, because the steel alloying elements and temperature varies, but in the two-phase region approximately 1 hour after completion of 90%. Pearlite formed from the austenite, its carbon content close to the initial eutectoid composition (ie, about 0.77%)./p
pnbsp;nbsp;nbsp; b. heated to high temperature two-phase region/p
pnbsp;nbsp;nbsp; If the steel is heated to higher temperatures, the austenite region will be further expanded to the original ferrite, austenite carbon content will be gradually reduced to close to the steel composition. Original ferrite may form a small and isolated austenite./p
pnbsp;nbsp;nbsp; Cast steel in the two-phase region when warm and then cooled, the resulting lower body and transformed into Austria pearlite and ferrite. The main effect of treatment is to refine the grain structure, which can improve the toughness of the steel./p
p(2) heat treatment points/p
pnbsp;nbsp;nbsp; Important steel castings, during the heat treatment should be a uniform prior to annealing, to eliminate widmanstatten. Homogenization temperature is generally above A3 100-150 ℃, holding at this temperature after furnace cooling. General Steel Castings, you can not make this deal./p
pnbsp;nbsp;nbsp; In addition to the special requirements of steel castings, in general, the use of annealing, normalizing or quenching and other heat treatment process./p
pnbsp;nbsp;nbsp; The use of annealed steel castings, the requirements on the mechanical properties are generally not high, this type of casting, do not deal with the two-phase region./p
pnbsp;nbsp;nbsp; The use of normalizing or quenching of steel castings, such as the requirement to improve the impact properties, two-phase region can be dealt with experimental research, the following observations can be used as a reference test./p
pnbsp;nbsp;nbsp; a. the use of normalizing the situation/p
pnbsp;nbsp;nbsp; Carbon steel castings and low alloy steel castings, generally using normalizing or normalizing, tempering. Normalizing, the heating temperature should be in A3 above 30-50 ℃, holding time determined by the casting section thickness, usually every 25mm thickness for 1 hour./p
pnbsp;nbsp;nbsp; For two-phase zone heat treatment, casting will be handled by normalizing again heated to more than A1, A3 below a certain temperature, holding followed by air cooling. Specific values ??for A3 carbon steel and alloy element content is different, and can be found from the heat treatment manual, two-phase region deal with the specific temperature values ??determined by the test results can be used in the laboratory sample treated differently, and thus select the best temperature./p
pnbsp;nbsp;nbsp; After the need to temper such as normalizing, the tempering process should be carried out after the two-phase region./p
pnbsp;nbsp;nbsp; b. the case of using quenching/p
pnbsp;nbsp;nbsp; High requirements on the mechanical properties of low alloy steel castings, should quenching process, quenching, including quenching and tempering two processes./p
pnbsp;nbsp;nbsp; Cast steel quenching, the heating temperature is usually in A3 above 20-30 ℃./p
pnbsp;nbsp;nbsp; Quenched and tempered steel for two-phase heat treatment area should be carried out after quenching. Dealing with the above normalizing the selected temperature the same in the selected temperature after thermal quenching, quenching medium and the first quenching the same.br //p