Pipe fittings play an important role in the connection, controlling, direction changing, streaming components collectively sealed and supporting. Carbon steel pipe fittings are main auxiliary products for the steel pipe. The key products are carbon steel elbow, flanges, steel cap, steel tee, carbon steel pipe reducer. The standards include national standard, American standard and DIN.
Carbon steel pipe fittings also called pressure pipe fittings. It is usually divided into three types:butt class pipe fittings, socket welded pipe fittings and threaded pipe fittings. In pipe joints system, you need various sizes of steel pipe fittings due to the different pipe sizes. For example, the threaded pipe fitting is necessary for straight tube or tube section connecting. Because of the double characteristics of the tubes and mechanical elements, all pipe should belongs to the steel pipe fittings after finished the deep process of steel pipe.
The sides of the steel pipe are painted to guaranteed as the fittings or oxidation resistant metal like zinc or nickel with electroplating. But it is well-known that the out layer of steel tube is just a thin film that is easy to be damaged. Once the protective layer damaged, the steel tubes start to rust in the atmosphere. So the preservative is necessary for the carbon steel tube depending on the zinc, nickel and chromium as protective layer.
Such as spiral steel pipe weld gap is too large, the effect of cuts constituting nearby, eddy current lack of heat, weld crystal adverse indirect co-occurrence of cracks or lack of fusion; if the gap is too small, the effect is increased near constitute, excessive heat welding to form weld seam burning; perhaps weld by kneading, rolling after composing pit, affecting the quality of the weld surface of the tube is heated to a marginal two welding temperature, under kneading roll kneading, together constitute the metal grain mutual penetration, crystallization, ending spiral steel pipe welds constitute strong kneading force is too small if, together constitute the number of crystals is small, the weld metal strength decreases, cracking may occur after the force; If kneading excessive force will make the molten metal is extruded weld situation, not only reduces the weld strength, and the list will be a lot of glitches, and even take the welding seam constitute disadvantages.
Breakage of spiral pipe according to the material after the destruction of anti-corrosion steel case and metal material is substantially the same divided into three types, namely: ① cleavage fracture, ② tie troglobites anti-fracture, ③ slip surface separation fracture.
Cleavage fracture along a section strictly crystal - product surface separating the planes calledcleavage plane. When the fracture along the crystal plane, the theoretical minimum breaking strength. Decision cleavage plane of factors specific surface energy y, the surface of the crystal plane spacing mountains and modulus of elasticity along the normal direction. Cleavage fracture with almost no plastic deformation, is a brittle fracture occurs in the body-centered cubic, hexagonal close-packed gold center. Fcc metals is generally not cleavage fracture occurs. The nature of the genus L ductile material gold sessions, shear fracture is the main fracture mechanism. Such as anti-corrosion steel alloy second phase particles to impede slippage, increasing the resistance to plastic deformation; when the plastic deformation increases, the second phase particles and the matrix interfacial peeling occurs Aung, produce tiny hole; hole formed, grew up with the merger will form a shear section. For high-purity metals, for there is no second phase particles, double metal wear-resistant composite pipe and will not yield: Health and tiny holes, the results of the battle was only shifted along the surface area is increasing, and finally the formation of slip planes separate section. Anti-corrosion steel composite spinning technology under special equipment for precise control, re-pressed wheel rotation and liner friction generates heat quickly reach the softening point of stainless steel, roller squeeze out of the outer tube is elastically deformed, the two create an interference together to achieve closely. From gold session histological point of view, it is divided into the fracture and transgranular fracture along the fracture goods.
European hot-rolled coil prices remained stable in the past week, at €420~440/ton (about US$475~498/ton), the ex-factory price.
European domestic market demand for hot-rolled coil increased slightly week on week, due to resource requirements for buyers purchasing tendencies from the domestic market instead of book imports.
Due to anti-dumping investigations on imports of hot-rolled coil continues proceeding, and delivery times expected longer. In addition, the market demand is expected to remain weak during the summer vacation.
Spiral pipe factory should be done before the mechanical performance test and flattening test, and flaring test, and to achieve the standard requirements. Straight seam steel quality inspection method is as follows:
1, From the face of it, that is visual inspection. Visual inspection of welded joints is a simple procedure but widely used test method is an important part of product testing, the main defects and deviations are found on the surface of the weld size. Usually by the naked eye, with the standard model, gauge and test tools such as a magnifying glass. If the weld surface defects, weld defects there may be internal.
2, Physical test methods: physical test method is to use some physical phenomena assay or test method. Or within the workpiece material defect inspection, and are generally used NDT methods. NDT ultrasonic flaw detection, radiation detection, penetration testing, magnetic testing and so on.
3, Pressure vessels strength test: pressure vessels, in addition to tightness test, but also the strength test. There are common test of two hydraulic test and air pressure. They can be tested in working under pressure vessels and piping welds compactness. Hydrostatic pressure test is more sensitive than the test speed and, at the same time after the test products do not waste water treatment, drainage problems for the product is particularly applicable. But the risk is greater than the test pressure test. When tested, it must comply with the appropriate safety measures to prevent accidents during the test.
4, Compact test: liquid or gas storage vessel welding, which is not dense weld defects, such as penetrating cracks, pores, slag, incomplete penetration loose tissue and the like, can be used to find the density test. Compactness test methods are: kerosene test, carrying water testing, water will test etc.
5, Hydrostatic test: each pipe hydrostatic test should be done without leakage test pressure press Calculate P = 2ST / D where S- hydrostatic test stress test Mpa, hydrostatic test stress testing in accordance with corresponding steel standard specifies the minimum degree of yield (Q235 is 235Mpa) 60% of the selection.
Recently, Newcomers of Shinestar Group attended the 2016 new employees training activities. In order to make the new staff are more involved in the working, to get deeper understanding of the Shinestar ’s corporate culture, to adapt to new environment, to enhance the sense of belonging and increase the skill of working for the new staff.
Achievement of internal staff ,Achievement of external customers is the company's mission.The group has always attached great importance to the training and shaping of the staff. Every year for the growth of new employees, reserve personnel training and vocational skills upgrading, and also there is a detailed training program. With the development of the enterprise, personnel change constantly new employee orientation, some new people just out of college, some staff just converting industry, for industry, companies are not quite understand, in view of this situation, the HR Department of the group from the industry, company and used to develop a career, career planning, careful arrangements, organize the training for new employees of the industry, the company has a full range of understanding.
On the first work day,every new employee will get a special notice which complied carefully by the group . The notice could let new employee familiar with company environment, solving the problem of live and all kinds of office matters. In the next half a month's time, Group will hold training for new employee, functional departments answer question meeting, professional business training (such as customer development mentality and attitude adjusting, etc.) and visit the factory .
In all training activities, the special Shinestar characteristic is visit steel pipe's factory. As the bench-marking enterprise of steel service field, product production is the basic and most important. Visiting factory workshop,combining theory with practice, which makes newcomers have deeply understanding on product and the steel industry, provides great help for business development. On the other side, factory visiting makes newcomers understand the powerful of the company, which helps to improve the sense of company honor and belonging.
Targeted induction activity, is the cradle of newcomer growth, it will be a good start in their careers. After the training, the new employees will be as fresh blood into various positions of Shinestar Group, which in future work, they will use their enthusiasm and professional to contribute to the development of the group and the industry.
Select of Straight Seam Submerged Arc Welded Steel Pipe
(1) For high peak load requirements of the pipeline, because the user's gas consumption is very uneven, pipeline pressure fluctuations in the frequent, alternating stress steel to withstand large tubing will expand the existing defects in alternating stress, if more choice weld defects high probability of spiral welded steel pipe, the safe operation of the pipeline will not be guaranteed.
(2) Pipeline crossing earthquake fault or by topical highly seismic region, due to the geological activity of these lots frequent pipeline will have a vertical or axial alternating stresses. Spiral weld much higher than the probability of defect LSAW steel pipe, under long-term stress, spiral welded steel pipe is much higher than the probability of an accident LSAW steel pipe, therefore, in such areas should be used straight submerged arc welded pipe.
(3) Internal and external coating requires a high piping should be used LSAW. Spiral submerged arc welded pipe weld more general than the weld reinforcement LSAW high, when the steel pipe internal and external corrosion, anti-corrosion materials and combination of the bare tube is not as close LSAW, anticorrosive effect is not good LSAW steel pipe.
(4) For important wear across the engineering, use LSAW. Due to difficulties in future maintenance and management than the general line segment, therefore, the use of excellent performance LSAW particularly necessary.
(5) For the pipeline weaknesses, such as heat and simmer elbow pipe should be used LSAW. Heat simmer elbow since the direction of change, their exposure to internal and external forces than the general line of straight pipe should be large, due to the impact of various factors in the simmering process, it is not easy to eliminate stress, is a long-distance pipeline in the weak link , integrated performance good LSAW can make up for these deficiencies.
When a piping project not works well, the steel pipes and pipe fittings are always facing the wear resistant problem ,especially when some impurity, sands,slurry in the flowing liquid . Some technical measures should be taken to reduce wear and tear about pipe and fittings .
1.We should assess the liquid condition when choose the steel material of the pipe fittings . Should we use the common steel material? or the wear resistant steel ? or should we arrange the wear resistant coating or lining materials? cement lining or ceramic lining?
2. The special treatment for pipes or pipe fittings. For example , the steel elbows. The outer radius of the elbow is grinded most seriously, we can add some thickness to this part of the elbows. This is also happened to other pipe fittings, like tees , reducers.
3. To the steel pipes , concentric reducers and caps , they can rotate in any degree and piping system . When they are in the horizontal direction , due to wear of the maximum bottom, on both sides, followed by the top of the minimum, therefore, the pipes an fittings could periodically inverted, it will extend the life of the piping system .
4.The position, direction and the angle of the pipe fittings also will effect the abrasion situation . If the position is not suitable , the flowing liquid will cause cavitation. The cavitation will speed up the abrasion of the pipings
Spiral pipe stacked right help protect the quality of spiral steel pipe, spiral steel pipe prolong life, prevent deformation, erosion, so orderly stacking spiral steel pipe, but also conducive to late spiral pipe loading, inventory. Spiral Pipe buyers should also strictly in accordance with the requirements of spiral steel pipe pile.
1) Spiral pipe open dumps, following necessary pad with wood or stone, stack surface needs slightly tilted to facilitate drainage, and pay attention to the material placed flat to prevent the causing bending.
2) Spiral pipe principle requires stacking under palletizing firm to ensure the safety of the premise, to do according to species, palletizing specifications, different varieties of materials to palletizing respectively, to prevent muddy and mutual erosion, but also easy to install a library car.
3) Prohibit storage of steel aggressive action items in spiral steel pipe pile position around.
4) Spiral steel pipe pile bottom should be padded, strong, smooth, prevent moisture or material deformation,
5) The same material by successively respectively stacking storage.
6) Sspiral steel stacking height, artificial homework does not exceed 1.2m, mechanical homework does not exceed 1.5m, stack no larger than 2.5m,
7) Be left between the stacks and stacks of certain passages, check road is generally O. 5m, of access depending on the size and material transport machinery, generally is 1.5 ~ 2.0m,
8) Open dumps angles and channels should stoop to put that mouth down, beam shall stand up, you can not be up and groove steel to avoid rusting water.
9) The end of booster stack, if the warehouse sunny cement floor, to elevate O.1m, if the mud shall booster O.2 ~ 0.5m. If it is open space, concrete floor booster 0.3 to 0.5 m, the surface mud booster 0.5 ~ 0.7m.
Size deviation mainly in the SSAW steel pipe is straightness, roundness, aspects of uneven thickness.
In most cases, straightness tolerance for the use of spiral steel pipe under large, but the manufacturing standards for spiral pipe straightness requests, if the predetermined value is exceeded, would constitute a reason to return, and therefore, spiral pipe plant should still be noted.
Roundness tolerance will affect the use of spiral steel pipe, mainly in the group of the wrong side of the welding head. Roundness tolerance has led to the wrong side of the welded joint will not only reduce the pressure capability, but also stress concentration. When the site Group, roundness some pipe can be corrected. Outside diameter deviation and the impact on the spiral steel pipe used roundness tolerance fairly.
Non-uniform wall thickness generally easy to be ignored, and many spiral steel pipe standards are not clearly defined. If the wall thickness Uneven, it will not only result set to the wrong side of the joint, but also the secondary deformation processing (such as steel pipe manufacturing pipe) adversely affected.
On engineering, process operating parameters should not be used directly as a pressure pipeline design conditions, factors to consider process operating fluctuations, the impact of connected devices, environmental impact, etc., and on the basis of operating parameters of the process are given a certain amount as a design safety margin condition. Design conditions mentioned here mainly refers to the design pressure and design temperature.
SSAW steel pipe design pressure: when should not be less than the normal operating pressure under the most demanding conditions by the internal pressure (or external pressure) and temperature constituted.
The most severe conditions: is the lead pipe and piping components maximum wall thickness or the maximum nominal pressure rating conditions.
Design pressure determination: consider the medium hydrostatic pressure and other factors, the design pressure should generally be slightly higher than the maximum working pressure under the most demanding conditions by (or on) the external pressure and temperature constituted.
The hot-extrusion process consists of enclosing a piece of metal, heated to forging temperature, in a chamber called a “container” having a die at one end with an opening of the shape of the desired finished section, and applying pressure to the metal through the opposite end of the container. The metal is forced through the opening, the shape of which it assumes in cross-section, as the metal flows plastically under the great pressures used.
Tees using raw material with a bigger diameter than the finished product, the branch outlet is extruded from pipe while the main body is being pressed. The outlet’s wall thickness can also be adjusted as needed. Applied to Tees with large diameters, heavy wall thickness and/or special material with challenging workability that cannot be manufactured using the hydraulic bulge method.
Various types of scaffolding fire should work closely with the construction site fire protection and measures should primarily do the following:
1) scaffolding should be placed near a number of fire extinguishers and fire-fighting equipment, should understand the basic usage and basic knowledge of fire extinguishers. 2) must be cleared up on the scaffolding and Lee carried away construction debris around 3) on the temporary scaffolding or scaffolding near the hot work must be handled in the hot work permit, prior to clean hot work site or non-combustible materials are separated, fire-fighting equipment configuration, and a personal supervision, with the flare types of cooperation, coordination. 4) no smoking on the scaffolding. Strictly prohibited foot rack or store near combustible, flammable and explosive chemical materials and building materials. 5) manage the power supply and electrical equipment, power production must be stopped to prevent short circuits, maintenance or operation of electrical equipment under power to prevent arcing or spark damage scaffolding, or even cause a fire burned down the scaffolding.
6) use of fire (welding, gas welding, torch, etc.) according to the Fire Services Ordinance and construction unit, construction units apply the provisions of the use of fire and approval procedures, approval and taken certain security measures before being allowed to work.