steel pipe

　　Hot-rolled seamless steel pipe defects 　　a. Inner surface defects 　　1. An inner flap: presenting a straight line, a spiral or a semi-helical sawtooth defect on the inner surface of the steel pipe. 　　2. inside scarring: scars in the steel pipe inner surface, generally easily peel off. 　　3. Warping: a straight line or intermittent small nail-like tilt leather. Often seen in the capillary head, and easy to peel. 　　4. inside straights: a straight shape scratch with a certain width and depth. 　　5. inner edge: a straight shape protrusion with a certain width and depth. 　　6. inner drum kits: a super and regular protrusion and outer surface is not damaged. 　　7. Pull pits: a regular or non-regular pit and the outer surface without damage. 　　8. internal thread (this defect produced only at Accel units): spiral traces often seen in the thin-walled tube surface, and there are obvious rugged feelings. 　　b. outer surface defects 　　1. An outer fold: the outer surface of the p...

　　High frequency welding influence on welding quality of steel pipe 　　Steel weld gap control 　　Adjusting the amount of pressing the squeeze roll is maintained across the weld flush with the opening angle of 7 degrees or less, the gap control between 1-3 mm. Weld control is too large, it may appear poor welding, weld cracking produce incomplete fusion or weld control is too small, due to the excessive heat, weld likely to cause burning, molten metal splash, build-up is too large, affecting the quality of welding. (Splatter reasons: melt extrusion tube side, the internal pressure is greater than the surface of the weld steam pressure) 　　Regulation of high-frequency induction loop position 　　Induction coil placement should be in the same center line pipe, induction loop front roll center line distance from the squeeze, squeeze rollers under the premise does not burn , depending on pipe size as close, too far away when the heat affected zone width, weld strength will decrease. Coup...

　　Insulation steel pipe refers to that pipes: the process through the insulation after processing in different working environment and the role of media outside the guaranteed operating temperature and the surface temperature of the inner tube meets or meet the requirements of the steel pipes . Insulation steel pipe is made of steel tube, fiberglass inner sheath, fiberglass shell composition. Insulation pipe is a way to raise the temperature of the steel tube warmth in people's daily lives are often used, which has been so widely accepted and used. Widespread use of pipe insulation and construction, fitting and plumbing, the pipes can be a good guarantee the normal and smooth. 　　Insulation pipe is widely used in liquid and gas pipeline network, chemical pipe insulation works in petroleum, chemical, centralized heating network, central air conditioning and ventilation pipes, municipal engineering. High prefabricated thermal insulating tube is a good insulation properties, plus saf...

　　1. The range of wall thickness of seamless steel tube is relatively wide, small diameter and large wall thickness and large diameter and large wall thickness can be achieved, but in general, the length is limited (only a small number of manufacturers can produce extra long pipes). Relatively thin, can achieve large diameter and small wall thickness and small diameter and small wall thickness. Theoretically, how long is the long coil, welding, how long can the tube produce. Generally speaking, the thicker the more suitable for seamless steel pipe, the thinner the more suitable for welding pipe. 　　2. In terms of wall thickness uniformity and concentricity, welded pipe is better than seamless pipe. Because the thickness tolerance of the cold-rolled sheet is relatively uniform, the deformation during the forming process is uniform. However, the weld seams are protruding, and different companies and specifications have different welding height requirements. In special cases, it can be w...

　　A234 WPB steel pipe fittings is type of steel pipe fittings made by the material of ASTM A234 WPB. A234 steel pipe fittings are used for the pressure piping systems of moderate and high temperature services. ASTM A234 is the standard of pipe fittings material , it indicates the materials properties of different kinds of carbon steel and alloy steel, WPB is one of the steel grade in this standard . W means weldable, P means pressure, B is grade b ,refer to the minimum yield strength , like the astm A106 A53, Gr.B or API 5L Gr.B. A234 WPB is the most common carbon steel pipe fittings material . 　　A234 WPB pipe fittings are butt welding ends , commonly used to be welded with the steel pipes of A106, A53, GR.B material, or API 5L GR.B material. 　　Type of the ASTM A234 WPB steel pipe fittings : The regular products of A234 WPB pipe fittings are elbows, tees, reducers, caps, cross . There are seamless and ERW A234 WPB pipe fittings, the seamless A234 WPB pipe fittings means the fittin...

　　No matter which kind of scaffolding products (such as scaffolding plank, scaffolding coupler and so on) you shall buy, you should pay attention to the load of each type of them as different load shall cause various result during the whole engineering project. 　　First of all, there are three main concepts for us to get. Load among scaffolding products shall contain load transfer, construction load and static and live load. 　　Load transfer: The load transfer on the scaffolding is generally transferred from the foot plate to the small bar. And then, the small bar shall transfers to the big bar, then to the pole through the fastener or binding point, and finally reaches to the base and foundation through the bottom of the pole. 　　Construction load: According to some principles, bearing scaffolding’s original provisions scaffold construction load should not exceed 270kg/m2. Recent years, with the development of technology, finally, the scaffold safety technical specifications deter...

　　(1) Since the length of the SAW weld is approximately 4-5 times the length of the ERW weld, the internal welding knob has no process ability to remove it, so the friction of the inner wall of the pipeline is inevitably increased when conveying the medium. The ERW welding seam has a short length, and the internal welding knob can be removed. When the medium flows in the pipeline, the friction generated on the inner wall of the pipeline is smaller than that of the spiral seam submerged arc welded steel pipe. It is very advantageous to reduce the temperature rise caused by friction. 　　(2) According to the results of the residual stress measurement, the internal stress of the ERW welded pipe in the circumferential forming is small, which is beneficial to the pipe. For the SAW welded pipe, due to its large weld area, there are tension and pressure in the weld. The stress state is more complicated than that of the ERW pipe, which is related to the forming process of the spiral welded pip...

　　Hot rolled uses the slab continuous casting slabs as raw material, the reheating furnace heating, high-pressure water in addition to the scales into the roughing mill, roughing material by cutting heads, tails, and then into the finishing mill, the implementation of computer-controlled rolling system, after the final rolling through laminar cooling (computer-controlled cooling rate) and the take-up reel, become straight hair volume. Straight hair volume of head, tail often showed poor tongue and tail shape, thickness, width, precision, often there is wave-shaped edges, folding, pyramid and other defects. Its volume weight heavier, coil inner diameter of 760mm. (generally prefer to use the pipe industry.). After the straight hair volume is by cutting head, cut tail, trimming and multi-pass straightening, leveling and other finishing line treatment, and then cutting board or heavy volume, it becomes: hot steel, hot-rolled steel coil leveling, sitting with other products. Hot rolling f...

　　We often say that the hot expanding steel pipe is hot expanded seamless pipes, which is relatively low density but the contraction of the strong steel pipe ( seamless pipe ) can be referred to as thermal expansion. A process of skew rolling or drawing method to expand the pipe diameter. Steel pipe thickening in a short period of time, can produce non-standard and special types of seamless tubes with low-cost and high production efficiency, the current international developments in the field of tube rolling. 　　Hot expand pipe is by expanding the diameter of pipe to finish processes - thermal expansion process of the production of steel pipe. Hot expansion pipe are commonly referred to hot expanded seamless steel pipes. 　　So far, the thermal expansion carbon steel pipe production technology is relatively mature, the level of equipment and methods of thermal processing also has made substantial progress. From billet to the basic technological principle is still tube rotary piercing ...

　　The seamless steel tube is still quite a substitute in the production process. The reason for this situation of the seamless steel tube is that the forming gap changes too much, there are small burrs or small gaps on the edge of the strip, the forming is wrong, the welding wire diameter is uneven, and the welding wire joint. Unsmooth, uneven hardness of the wire causes uneven wire feeding, and metal burrs cause instant shorts at the tip. In this case, there is no need to make large adjustments, and the edge of the strip can be smoothed when conditions permit, and the molding can be kept stable. 　　The seamless steel tube is a pipe material whose welding seam is basically parallel to the steel pipe. The production process is simple, the production efficiency is high, the cost is low, and the development is fast. Generally, the curvature of the free side is ideal, but the delivery side is different. Due to the limitation, the deformation on the delivery side is not as good as the defo...