Hot New Products Galvanized Steel Square Pipes - Spiral Seamless Welded Pipe – JINBAICHENG

Product Introduction

Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have been increasing. Seam the steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of welds. Classification by production method: process classification-arc welded pipe, resistance welded pipe, (high frequency, low frequency) gas welded pipe, furnace welded pipe.

Smaller diameter welded pipes are welded by straight seam, while large diameter welded pipes are mostly spiral welded. According to the shape of the end of the steel pipe, it is divided into round welded pipe and special-shaped (square, rectangular, etc.) welded pipe; according to different materials and uses, it is divided into mining fluid Conveying welded steel pipes, galvanized welded steel pipes for low-pressure fluid conveying, electric welded steel pipes for belt conveyor rollers, etc. According to the size table in the current national standard, sort by outer diameter * wall thickness from small to large.

Product Display

Product Standards

Commonly used materials for welded pipes are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

The blanks used for welded steel pipes are steel plates or strip steels, which are divided into furnace welded pipes, electric welded (resistance welded) pipes and automatic arc welded pipes due to their different welding processes. Because of its different welding forms, it can be divided into two types: straight seam welded pipe and spiral welded pipe. Because of its end shape, it is divided into round welded pipe and special-shaped (square, flat, etc.) welded pipe. Welded pipes are divided into the following varieties due to their different materials and uses:

GB/T3091-2008 (Welded steel pipes for low pressure fluid transportation): Mainly used to transport water, gas, air, oil, heating water or steam and other generally lower pressure fluids and other purposes. Its representative material is: Q235A grade steel.

GB/T14291-2006 (Welded Steel Pipe for Mining Fluid Transport): Mainly used for straight seam welded steel pipes for mine air pressure, drainage, and shaft discharge gas. Its representative material is Q235A, Grade B steel.

GB/T12770-2002 (Stainless steel welded steel pipe for mechanical structure): Mainly used for machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

GB/T12771-1991 (Stainless steel welded steel pipe for fluid transportation): Mainly used to transport low-pressure corrosive media. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.
In addition, welded stainless steel pipes for decoration (GB/T 18705-2002), stainless steel welded pipes for architectural decoration (JG/T 3030-1995), and welded steel pipes for heat exchangers (YB4103-2000).

Production Process

Longitudinal welded pipe has simple production process, high production efficiency, low cost and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. A narrower blank can be used to produce welded pipes with larger pipe diameters, and a billet with the same width can also be used to produce welded pipes with different pipe diameters. But compared with the straight seam pipe of the same length, the weld length is increased by 30-100%, and the production speed is lower.

Large diameter or thick welded pipes are generally made directly from steel blanks, while small welded pipes and thin-wall welded pipes only need to be welded directly through steel strips. Then after a simple polishing, drawing is fine.
Supplement: The welded pipe is welded with strip steel, so it is not as high as a seamless pipe.

Welded pipe process
Raw material uncoiling-leveling-end cutting and welding-looper-forming-welding-internal and external weld bead removal-pre-correction-induction heat treatment-sizing and straightening-eddy current testing-cutting-water pressure inspection-pickling-final inspection (Strictly check)-packaging-shipping.

Classification

Classified by purpose
It is divided into general welded pipe, galvanized welded pipe, oxygen-blowing welded pipe, wire casing, metric welded pipe, roller pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welded thin-walled pipe, electric welded special-shaped pipe, scaffolding pipe and spiral welded pipe .

General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steel that is easy to weld. Steel pipes need to be subjected to water pressure, bending, flattening and other experiments, and there are certain requirements on the surface quality. Usually the delivery length is 4-10m, and the fixed-length (or double-length) delivery is often required. The specifications of welded pipes are expressed by the nominal diameter (mm or inches). The nominal diameter of welded pipes is different from the actual ones. According to the specified wall thickness, the welded pipes are available in ordinary steel pipes and thickened steel pipes. The steel pipes are divided into two types with thread and without thread according to the tube end form.

Galvanized steel pipe: In order to improve the corrosion resistance of the steel pipe, the general steel pipe (black pipe) is galvanized. Galvanized steel pipes are divided into two types: hot-dip galvanizing and electro-galvanizing. The hot-dip galvanizing layer is thick and the cost of electro-galvanizing is low.

Oxygen-blowing welded pipe: Used as a steel-making oxygen-blowing pipe, generally small-diameter welded steel pipes are used, with eight specifications ranging from 3/8 inch to 2 inch. It is made of 08, 10, 15, 20 or Q195-Q235 steel belt. In order to prevent corrosion, some are aluminized.

Wire casing: Ordinary carbon steel electric welded steel pipe, used in concrete and various structural power distribution projects, the commonly used nominal diameter is from 13-76mm. The wall of the wire sleeve is thin, and most of it is used after coating or galvanizing, and a cold bend test is required.

Metric welded pipe: The specification is used as a seamless pipe form, and the welded steel pipe expressed by outer diameter * wall thickness mm, using ordinary carbon steel, high-quality carbon steel or general energy low alloy steel for hot strip, cold strip welding, or hot strip welding Then it is made by cold dialing method. Metric welded pipes are divided into general energy and thin-walled, and are commonly used as structural parts, such as transmission shafts or conveying fluids. Thin-walled pipes are used to produce furniture, lamps, etc., and the strength and bending test of the steel pipe must be ensured.

Roller tube: Electric welded steel pipe for the roller of belt conveyor, generally made of Q215, Q235A, B steel and 20 steel, with a diameter of 63.5-219.0mm. There are certain requirements for the tube bending, end face to be perpendicular to the center line, and ellipticity. Generally, water pressure and flattening tests are carried out.

Transformer tube: It is used to manufacture transformer radiator tubes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending, and hydraulic tests. Steel pipes are delivered in fixed-length or double-length, and there are certain requirements for the bending of the steel pipe.

Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, hollow rubber steel doors and windows welded by ordinary carbon structure steel and 16Mn steel strips, mainly used for agricultural machinery parts, steel windows and doors, etc.

Welded thin-walled pipe: mainly used for making furniture, toys, lamps, etc. In recent years, thin-walled tubes made of stainless steel belts are widely used, such as high-end furniture, decorations, and fences.

Spiral welded pipe: It is made by rolling low-carbon carbon structural steel or low-alloy structural steel strip into a tube blank at a certain spiral angle (called forming angle), and then welding the tube seam together. It can be made with a narrower Strip steel produces large diameter steel pipes. Spiral welded pipes are mainly used for oil and natural gas pipelines, and their specifications are expressed by outer diameter * wall thickness. Spiral welded pipes can be welded on one side and on both sides. The welded pipe shall be guaranteed to meet the requirements in terms of hydraulic test, tensile strength and cold bending performance of the weld.

Longitudinal welded pipe specification table

Spiral welded pipe specification table

Note: Ministry standard refers to SY/T5037-2000 standard.