Tips for using heat-resistant steel

‌Tips for using heat-resistant steel mainly include welding skills and material selection. ‌

Welding skills
‌Welding methods‌: There are many methods for welding heat-resistant steel, commonly used are arc welding, submerged arc welding and tungsten inert gas welding. For chromium-molybdenum heat-resistant steel, the commonly used welding methods are tungsten inert gas welding for base laying and arc welding for filling and covering. Other methods include melt inert gas shielded welding (MIG welding), CO2 gas shielded welding, electroslag welding and submerged arc automatic welding‌.
‌Welding materials‌: When selecting welding materials, it should be ensured that the alloy composition and strength properties of the weld metal are consistent with the corresponding indicators of the parent material, or meet the minimum performance indicators specified in the product technical conditions. Low-hydrogen alkaline electrodes are a better choice. The electrodes or flux should be dried according to the specified process and taken out as needed‌.
‌Welding process measures‌: To prevent reheat cracks, welding materials with better high-temperature plasticity than the parent material should be selected, the preheating temperature and interlayer temperature should be appropriately increased, and low heat input welding methods and processes should be adopted to shorten the holding time in the sensitive temperature range. Reasonable design of joint form to reduce joint constraint‌.
Material selection
‌ Low alloy heat-resistant steel‌: This type of steel mainly improves creep strength and structural stability by adding alloying elements such as Cr, Mo, V, and Ti. Its carbon content is usually controlled below 0.2% to ensure good weldability‌.
‌ Medium alloy heat-resistant steel‌: The main alloying element is Cr. As the Cr content increases, the high temperature resistance and high temperature oxidation resistance are improved. Elements such as Mo are often added to improve creep strength and reduce temper brittleness‌.
‌ High alloy heat-resistant steel‌: It has high mechanical properties and oxidation resistance above 600℃ and is often used for key components in high temperature environments. Alloy elements include Cr, Ni, W, V, Mo, etc.‌. By mastering these techniques and choosing appropriate materials, the use and life of heat-resistant steel can be effectively improved.