How to accurately identify the seamless pipe rust or not?
The seamless steel square tube production requires you to understand? Seamless square tube will appear normal floating rust phenomenon, but how to distinguish the seamless tube is normal floating rust aluminium coated tubes or rust? Seamless square tube manufacturer below small make up for you to introduce about it. Seamless tube is through steel tube billet section, then in the annular furnace heating - punch - sizing - alignment - cooling - play head - packaged as qualified products, generally in to use in production workshop is not put so much on the spot, this would require the dealer place Some spot, but the dealer typically have large indoor library, there are cost is too high, if it's not worthwhile. Is it mostly outdoor warehouse, seamless square tube lying outside the wind is inevitable rush sun exposure.
So-called floating rust just as its name implies is to float to the seamless tube above a layer of rust, towels or other things a bit can be removed, simply floating rust is not rust, belongs to the normal state. Seamless pipe rust is years old, at least 1 year Above outside after the wind rush sun of seamless pipe, seamless square tube with rusty, large and small, ma pit, which is the only biggest seamless tube floating rust and rust.
There are three kinds of steel, common quality problems: 1, the surface crack surface quality defects: refers to the phenomenon of crack of steel surfaces in a straight line shape, the general should be the same as that of forging or rolling. Reasons: mainly because in processing (forging, rolling, heat treatment Burnt in the process of tempering) due stainless steel tube 304 to surface, decarburization, loose, deformation and internal stress is too large, and surface of sulphur, phosphorus content of impurities is more hair lines, hot crack and cold crack.
Surface crack can be observed by the naked eye, pickling, magnetic particle testing, dye penetrant inspection Inspection and metallographic method. Upon confirmation of crack, must pay attention to distinguish between the oxide coating on the surface of the steel itself very brittle crack in loose after slightly bent and rendering, and steel itself did not crack. 2, double skin and folding: steel bond is the tongue Or squamous metal chips in the local surface formation overlap, there is a clear fold lines. Forming reason: because of the billet in the process of hot working on flash, burr, concave, inclusions, such as subcutaneous blowhole Cold Drawn Seamless Tubes and loose surface, the metal flow during hot deformation Changes, opening to form a double skin and folding.
3, handle: refers to the steel surface concave up along the rolling direction outspread. Formation: mill roller clearance is too large, makes the pore formation on the surface of steel.
4, scratch: also called scratch, refers to in the steel surface Under the action of external force in a straight line or arc trench (visible to the bottom). 1 second, the internal defects, segregation, is actually in steel chemical composition does not divide the floorboard of the phenomenon.