The differences between cold-rolled seamless steel pipes and hot-rolled seamless steel pipes

The core difference between cold-rolled seamless steel pipes and hot-rolled seamless steel pipes lies in the different temperatures of the ‌ manufacturing process, which leads to differences in performance, precision and application fields ‌ : hot-rolling is carried out at high temperatures, while cold-rolling is processed at normal or low temperatures. ‌ ‌

Differences in manufacturing processes

Youdaoplaceholder0 hot rolling process ‌ : Heat the steel billet above the recrystallization temperature (usually above 1200℃), and continuously roll it into shape through rolls, which can refine the grain structure and improve mechanical properties. ‌ ‌

Youdaoplaceholder0 cold rolling process ‌ : At room temperature, it is processed through cold drawing, cold drawing or cold rolling. Multiple drawing and annealing treatments are required to eliminate work hardening, making the process more complex. ‌ ‌ ‌ ‌

Performance and dimensional characteristics

Youdaoplaceholder0 mechanical properties ‌ :

Hot-rolled pipes have good toughness and are easy to process and weld, but their strength is relatively low. ‌ ‌

Cold-rolled tubes have higher strength, hardness and fatigue resistance, but poorer toughness. ‌ ‌

Youdaoplaceholder0 dimensional accuracy ‌ :

The outer diameter of hot-rolled pipes is generally greater than 32mm, with a wall thickness ranging from 2.5 to 75mm. The dimensional accuracy is relatively low and the surface may be rough. ‌ ‌

The outer diameter of cold-rolled tubes can be as small as 5mm, the wall thickness as thin as 0.25mm, with high precision (tolerance ±0.05mm) and good surface finish (Ra0.8μm). ‌ ‌