Q235B steel pipe is a steel pipe made of strip steel coils as raw materials, often extruded at temperature, and welded by automatic double-wire double-sided submerged arc welding.
Production Process
The raw materials are strip steel coils, welding wire, and flux. Strict physical and chemical tests are required before investment. The strip steel head and tail are butt jointed by single-wire or double-wire submerged arc welding, and automatic submerged arc welding is used for repair welding after coiling into steel pipe. Before forming, the strip undergoes leveling, edge trimming, edge planing, surface cleaning and conveying, and pre-bending treatment. Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor to ensure the smooth delivery of the strip. Adopt external control or internal control roll forming. The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are strictly controlled.
Both internal welding and external welding use American Lincoln electric welding machines for single-wire or double-wire submerged arc welding, so as to obtain stable welding specifications. The welds are inspected by an online continuous ultrasonic automatic flaw instrument, which guarantees 100% non-destructive testing coverage of spiral welds. An air plasma cutting machine is used to cut the steel pipe into individual pieces. After cutting into single steel pipes, the first three steel pipes of each batch shall undergo a strict first inspection system to ensure that the pipe-making process is qualified before being officially put into production. The parts with continuous sonic flaw detection marks on the welds undergo manual ultrasonic and X-ray re-examination. The pipes where the strip butt welds and the D-shaped joints intersecting the spiral welds are all inspected by X-ray television or filming. Each steel pipe undergoes hydrostatic pressure test, and the pressure adopts radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. The test parameters are automatically printed and recorded. The pipe end is machined to accurately control the verticality of the end surface, the bevel angle and the obtuse edge.
Q235B Steel Pipe Specifications
| Production Range | · SSAW OD: 219mm – 3120mm WT: 3mm – 25mm· LSAW OD: 16″-64″ WT: max 50mm · ERW · SMLS |
| Codes and Standards | ANSI, ASME, ASTM, API, SAE, BS, AGA, AWWA, ISO, DIN |
| Dimensions | ASME/ ANSI B36.10 / 19 |
| Pipe schedules | SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS |
| Producing techniques | Seamless / ERW / Welded / Fabricated / CDW / EFW |
| Available Shapes | Round, Half Round, Square, Rectangular or Custom shape |
| Length | 3 to Max18 Meters or custom |
| End | Beveled End, Plain End, Treaded |
| Test Certificate | EN 10204 3.1 B |
| Length | Random Length / Fixed Length / SRL / DRL |
| Usage | Mechanical Tubing Liquid Transport Steel Pipe General structure, mechanical structure Transport liquid, gas, oil |
| Test | · Chemical Component Analysis
· Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation) · Technical Properties (Flattening Test, Blow Test, Impact Test, Flaring Test, Bending Test, Hardness Test etc) · Exterior Size Inspection · Nondestructive Test (Ultrasonic flaw detector, Eddy current flaw detector) · Hydrostatic Test |
| Surface | Fusion bond Expoxy Coating / Coal Tar Expoxy / 3PE / Varnish Coating Bitumen Coating / Black Oil Coating as per customer’s requirement |
| Mill Test Certificate | EN 10204/3.1B |
Q235B Carbon Steel Pipe Composition
| Grade | Chemical Composition | |||||
| C | Mn | Si | S | P | ||
| Q195 | 0.06-0.12 | 0.25-0.50 | ≤0.30 | ≤0.045 | ≤0.05 | |
| Q215 | 0.09-0.15 | 0.25-0.55 | ≤0.30 | ≤0.05 | ≤0.045 | |
| Q235 | 0.12-0.20 | 0.30-0.67 | ≤0.30 | ≤0.045 | ≤0.04 | |
| Q345 | ≤0.20 | 1.00-1.60 | ≤0.55 | ≤0.04 | ≤0.04 | |
Steel Grade Q195 Pipe Mechanical Properties
(N/mm2 = Mpa)
| Grade | Yield Strength | Tensile Strength |
| Q195 | 195 | 315-430 |
| Q215 | 215 | 335-450 |
| Q235 | 235 | 370-500 |
| Q275 | 275 | 410-540 |
Features
Straight seam 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 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. Therefore, most of the smaller diameter welded pipes adopt straight seam welding, and the large diameter welded pipes mostly adopt spiral welding.
Standard Classification
Spiral seam submerged arc welded steel pipe (SY5036-83) for pressure-bearing fluid transportation is mainly used for pipelines for transporting oil and natural gas; spiral seam high-frequency welded steel pipe (SY5038-83) for pressure-bearing fluid transportation, using high-frequency lap welding method Welded, spiral seam high-frequency welded steel pipe for pressure-bearing fluid transportation. The steel pipe has strong pressure-bearing capacity and good plasticity, which is convenient for welding and processing. Generally, the spiral seam submerged arc welded steel pipe (SY5037-83) for low-pressure fluid transportation is made by double-sided automatic submerged arc welding or single-sided welding for water, Submerged arc welded steel pipe for conveying general low pressure fluids such as gas, air and steam
The commonly used standards of Q235B steel pipes are generally divided into: SY/T5037-2000 (Ministry standard, also called spiral seam submerged arc welded steel pipe for ordinary fluid transportation pipelines, GB/T9711.1-1997 (National standard, also called oil and gas industry delivery steel pipe delivery) The first part of the technical conditions: A grade steel pipe (to the strict GB/T9711.2 grade B steel pipe), API-5L (American Petroleum Institute, also called pipeline steel pipe; which is divided into two levels: PSL1 and PSL2), SY/ T5040-92 (Spiral submerged arc welded steel pipe for pile)
Q235B steel pipe material: Q235A, Q23b, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb. Q345 L245 L290 X42 X46 X70 X80
