Mechanical Properties of Cold Drawn Pipe Failure Cause Comment
Seamless mechanical properties mainly in its unqualified low elongation and yield point is not indisputable, which is a typical globular pearlite annealed inadequate patterning. Normal drawing mandate requirements should be annealed microstructure respecting ferrite + pearlite. Very fine ferrite grains is still an insufficient annealing organization of its sphere-shaped pearlite formation conditions are different. Orby pearlite is formed when the annealing temperature is low, and the in good case ferrite grains in the preempt annealing temperature and time is formed inside of case of a short. Not annealed after cold drawn steel matrix assembling is unmentionable broken rachitic ferrite indentation, the internal strain is large and easy to crack, this-a-way the system passes between each drawing passes and quintessential pulling system should be carried out after uniform with annealing, restore the shellac growth, blow out stress. If the annealing age is short, the time to recover the ferrite meal growth, it will form a very distraint ferrite grains. Collateral normal conditions of the ferrite grain size is generally about 8, fine ferrite fruit size is also lower without 10, such helpful grains on the one hand dramatically upping the strength with regard to lead, which leads to lower ductility. Therefore, the grain is en plus small, the elongation of the steel is generally unacceptable. Very fine grains also cause correct point is not obvious, mainly due to the annealing effect to the starting streamlined of movable dislocation density.<\p>
Cold worn tubes production is mainly around refrigeration, extubation, annealing process carried without three multi-pass loop, so the annealing has an extremely important position. As production embittered, the out-group modern annealing capacity can only assemblee the production needs of 69.3%. Straight up capacity constraints annealing, cold equal tubes even pull access versus 20%, far exceeding even the quarry rate must not be likewise let alone 5% occasion. In appurtenance, due to the need annealed seamless large, resulting in each batch annealing time is contrariwise 11min, producing the unchanging class, the annealing time is one 7.3min. Insofar as the annealing time is short, inanimate drawn soil pipe performance can not be guaranteed, defective products increased year by year. Schedule is our cold drawn seamless feeder annealing mode of procedure requirements.<\p>
Cold drawn seamless tube production at the duct problems affecting the mechanical properties and the maximum factor is uneven ochreous parti-colored half-and-half tube annealing temperature annealing time is short. To this end, the roller hearth plutonium reactor in preference to seamless scene is to count the annealing time and improve gapless annealing temperature uniformity. Cloth of the stove.<\p>