News & Updates

1. The difference between hot working and cold working: Hot rolling is a form of hot working, while cold drawing is a form of cold working.

Key differences: Hot rolling is performed above the recrystallization temperature, while cold rolling is performed below it. Cold rolling may sometimes involve heating, but at relatively low temperatures, as it results in work hardening. If high forming requirements are needed for the material, annealing is also required.

2. The difference between cold-drawn seamless steel tubes and hot-rolled seamless steel tubes differs from that of sheet metal.

Seamless steel tubes are classified into two types based on their manufacturing processes: hot-rolled (extruded) seamless steel tubes and cold-drawn (rolled) seamless steel tubes.

3. Cold-drawn (rolled) tubes are further classified into two types: round tubes and shaped tubes:

Cold-drawn steel tubes generally require multiple drawing passes, with corresponding stress-relief annealing between each pass to ensure the smooth progression of the next drawing operation. Visually, cold-rolled seamless steel tubes are often small in diameter, while hot-rolled seamless steel tubes are typically large in diameter. Cold-drawn seamless steel pipes offer higher dimensional accuracy than hot-rolled seamless steel pipes and are also more expensive. Cold-drawn seamless pipes generally have smaller diameters, mostly under 127 mm; in particular, the outer diameter of cold-drawn seamless pipes is characterized by very high precision. Cold-drawn seamless pipes are typically shorter in length than hot-rolled seamless pipes. In terms of wall thickness, cold-drawn seamless pipes exhibit greater uniformity than hot-rolled seamless pipes.