In the field of metal processing, cold rolled steel and hot rolled steel are two common materials, each with its own advantages and disadvantages in terms of strength, surface finish and welding performance. For welding operations, choosing the right steel is crucial because it directly affects the welding quality and efficiency.
Properties of hot-rolled steel - a welding-friendly choice
Hot-rolled steel is heated and rolled at high temperatures during production, and its internal structure is relatively uniform with coarse grains. This structure gives hot-rolled steel better ductility and toughness during welding, which can effectively relieve the stress generated during welding and reduce the occurrence of cracks.
Properties of cold-rolled steel - smooth surface, welding requires caution
Cold-rolled steel is made by further rolling hot-rolled steel at room temperature. It has a high surface finish and good dimensional accuracy, but its internal structure is relatively dense and the grains are relatively fine. This structure makes the strength and hardness of cold-rolled steel higher, but it also reduces its ductility and toughness. During the welding process, cold-rolled steel is more prone to cracks and deformation, so it is necessary to choose the welding process and parameters more carefully.
Cold-rolled steel vs. hot-rolled steel
Hot-rolled steel
Lower cost: The hot-rolling process is relatively simple and the production efficiency is high, so the price of hot-rolled steel is usually cheaper than cold-rolled steel.
Easy to process: Hot-rolled steel has lower strength and hardness, but better ductility and toughness, so it is easier to process such as cutting, bending, and welding.
Good mechanical properties: Hot-rolled steel has good tensile strength, yield strength, and impact toughness, and is suitable for structural parts that bear large loads.
Wide range of thickness: Hot-rolled steel can produce thicker plates, which is suitable for occasions where thick plates are required.
Cold-rolled steel
High surface finish: The cold rolling process can remove the oxide scale on the surface of hot-rolled steel to obtain a smooth and flat surface, which improves the aesthetics and corrosion resistance.
High dimensional accuracy: The steel has small deformation and high dimensional accuracy during the cold rolling process, which can meet the needs of high-precision processing.
High strength and hardness: The hardening effect of cold rolling increases the strength and hardness of the steel, which is suitable for occasions requiring high strength.
Excellent mechanical properties: Cold-rolled steel has good tensile strength, yield strength and fatigue strength, and is suitable for parts subjected to complex stresses.
Precautions when welding
Choose appropriate welding methods and parameters;
Use appropriate welding rods or wires;
Preheat and post-heat the weld;
Strictly control the welding environment to avoid moisture and dust.
Cold-rolled steel welding applications
Cold-rolled steel is used in many structural parts of automobile bodies, such as door inner panels, body frames, etc.
Cold-rolled steel is often used in the outer shells and internal structural parts of household appliances such as refrigerators, air conditioners, and washing machines. For example, the outer shell of a refrigerator is assembled by welding cold-rolled steel
Cold-rolled steel is also used in the manufacture of electronic equipment such as computer cases and mobile phone cases. These products have extremely high requirements for appearance and dimensional accuracy. The characteristics of cold-rolled steel enable it to meet the high-precision requirements of the product after welding.
Hot-rolled steel welding applications
Construction field
Steel structure bridges: Hot-rolled steel such as H-shaped steel and I-shaped steel are often used in the construction of steel structure bridges.
Industrial and civil buildings: Hot-rolled steel is also widely used in the steel structure frames of industrial plants and high-rise buildings. For example, the core tube structure of a high-rise building is welded with hot-rolled steel and can withstand the vertical and horizontal loads of the building.
Machinery manufacturing
Heavy machinery: In the manufacture of heavy machinery such as cranes and excavators, hot-rolled steel is the main structural material. Hot-rolled steel is welded and assembled into various parts of the machinery, such as the boom of a crane and the working device of an excavator.
Agricultural machinery: The frames and working parts of agricultural machinery such as tractors and harvesters are also often welded with hot-rolled steel. Hot-rolled steel has good corrosion resistance and wear resistance and can adapt to the harsh environment in agricultural production.
Xuanmin's products cover a variety of types and specifications of cold-rolled steel and hot-rolled steel welding. We can provide both small parts and large structural parts. We can quickly adjust the production plan according to the specific needs of customers, provide customers with one-stop procurement services, and help customers save procurement costs and time costs.
