ERW pipe issues and defects

ERW pipe issues and defects is related to raw materials, production methods, process conditions, equipment status and personnel.Product defects that appear in the production process by the above factors and constraints. This product defects can be divided into roughly two categories: one for product defects, that defects production of the product itself exist inconsistent sets of product standards; a class of defects generated during the production process defects, it do not form the product requirements of the standard items, but also an issue of product quality, and its trend of development will inevitably lead to product defects. Therefore, this defect is not allowed in the production process.
Process defects 
No burr: burr welds. Outer burr is generally better when the watertight test water pressure. But for Ling, bending, flattening test, weld most cracking.
Peach tip: weld at no glitches, and recessed within the wall, forming the tip shape of peaches, try water pressure when water-tight. But bending, flattening test, weld multiple cracking. Within the burr unilateral: watertight seam burr for the side extrusion test water pressure. Bending, flattening test, sometimes cracking.
Burnt: the outer surface of small pits in the weld, welding sparks a lot of splash, the microstructure observed small holes watertight when the test water pressure, bending, flattening test, most will not crack, but the impact on the intensity of use and life expectancy.
Weld defects 
Opening: straight weld plate edge face melting traces or melting traces without welding, crack two tip along the weld direction, expansion, penetrate the inner surface of the test water pressure, leaking.
Crack: micro-crack crack; the outer surface of the visible appearance of fine lines, the inner surface of intact, no leakage in the test water pressure, but when crushed or cold-formed crack.
Lap welding: two edge dislocation in the welding, scraping, except burrs can still see the obvious one side higher and exceed the wall thickness of the negative deviation.

Surface defects 
Scratch: the general was the axis of the straight channels and scratches, deeper than the wall thickness of the negative deviation of scrap defects in the weld on both sides of a continuous nail-shaped scratch. Super wall thickness of the negative deviation. Waste big flaw.
Correction hurt: the leveler spiral crushed obviously feel more than the wall thickness of the negative bias of – waste defect.
Pockmarked face: the tube surface successful piece punctate small pits with a diameter of about 1mm.
Warp: the pipe surface warping the separation of the part and the metal substrate into pieces, not continuous, spalling can not afford.