The difference between the ERW pipe and Seamless pipe

 

 

 

1.Production details:

STANDARD	GRADE	CHEMICAL COMPOSITION
		C	Si	Mn	P	S	Cr	Mo	Cu	Ni	V
ASME SA106	SA106B	0.170.25	≥0.1	0.701.00	≤0.030	≤0.030	≤0.035
ASTM A106	A	≤0.25	≤0.10	0.270.93	≤0.035	≤0.035	≤0.40	≤0.15	≤0.40	≤0.40	≤0.08
	B	≤0.30	≤0.10	0.291.06	≤0.035	≤0.035	≤0.40	≤0.15	≤0.40	≤0.40	≤0.08
	C	≤0.35	≤0.10	0.291.06	≤0.035	≤0.035	≤0.40	≤0.15	≤0.40	≤0.40	≤0.08
ASTM A53	A	0.25	/	0.95	0.05	0.045	0.40	0.15	0.40	0.40	0.08
	B	0.3	/	1.2	0.05	0.045	0.40	0.15	0.40	0.40	0.08
ASTM A179	A179	≤0.06-0.18	/	0.27-0.63	≤0.035	≤0.035
ASTM A192	A192	0.060.18	≤0.25	0.270.63	≤0.035	≤0.035
ASTM A210	A-1	≤0.27	≥0.10	≤0.93	≤0.035	≤0.035
	C	≤0.35	≥0.10	0.291.06	≤0.035	≤0.035

 

 

High-frequency straight seam resistance welding pipes (Electric Resistance Welding, referred to as ERW) and seamless steel pipe ERW biggest difference is that there are of welds, and this is the key to ERW pipe quality. Modern ERW pipe production technology and equipment, as the international community, especially the United States and other years of unremitting efforts, making the seamless steel pipe ERW have been more satisfactory solution.

Someone ERW seamless steel pipe seamless geometry and physics into seamless. Geometric seamless ERW steel pipe is to remove the internal and external burrs. Since the structure of the inner burr removal system and tool of continuous improvement and perfection, medium and large diameter steel pipe inside burr removal has been a good deal. Can be controlled within the burr-0.2mm ~ O.5mm so. Refers to the physical seamless weld microstructure inside there is a difference between the base material and weld area resulting in decreased mechanical properties, the need to take measures to make it uniform and consistent technology. ERW steel pipe for high-frequency welding thermal process, resulting in a temperature gradient is near the edge of tube and forming a molten zone, the semi-molten zone, overheating tissue, normalized area, areas not fully normalizing, tempering zones of the feature region. Which overheated zone tissue due to soldering temperature above 1000 ℃, the austenite grain grown dramatically in the cooling conditions will form a hard and brittle coarse crystalline phase, in addition to the presence of a temperature gradient will produce welding stress. Thus, the formation of the weld zone lower than the base metal mechanical properties of the situation is through physical seamless weld heat treatment process which uses local conventional induction heating device will weld area is heated to AC3 (927 ℃), then 60m length, the speed 20m / min during air cooling, water cooling when necessary. This method is used to achieve the elimination of stress, soften and refine the organization to improve the HAZ mechanical properties purposes. Currently, the world's advanced ERW unit This method has been widely used for processing of the weld has obtained good results. Quality can not be argued that not only ERW pipe welds and weld coefficient of 1, the realization of regional organizations of the weld and base metal of the match.

 

ERW steel pipe with both hot-rolled coil as a result of use of raw materials, wall thickness can be controlled within ± 0.2mm or so, according to the U.S. steel two-side APl standards or GB/T9711.1 standard repair side beat groove, cut length delivery and so on. In recent years, the natural gas pipeline network and gas companies have been widely adopted as Chengshiguanwang ERW pipe main pipe.