Spring steel is a kind of high-strength special steel with excellent elasticity and fatigue resistance, which is widely used in automobiles, machinery, electrical appliances, aerospace and other fields.
1. Material structure and characteristics
The main components of SUP9 are carbon (C), silicon (Si), manganese (MN), sulfur (S) and phosphorus (P), which has excellent toughness and heat treatability, and its material structure is mainly pearlite and bainite. Its main features are as follows:
1.High elasticity:SUP9 is widely used in the manufacture of heavy-duty springs, buffer springs, hydraulic springs, etc. due to its excellent elasticity.
2.Good fatigue resistance:SUP9 has a high fatigue life and is able to withstand long periods of repetitive loads.
3.Good solderability:SUP9 has good weldability and can be used to manufacture a variety of welded structures.
4.Good processability:SUP9 can be processed in a variety of ways, such as cold rolling, hot rolling, cold drawing, etc.
2. Metallographic structure and mechanical properties
1.Metallographic organization:The metallographic structure of SUP9 is mainly pearlite and bainite. Among them, pearlite is the main tissue, which has excellent toughness and plasticity; Bainite has high strength and hardness. The metallographic structure affects the mechanical properties of SUP9.
2.Mechanical Properties:The mechanical properties of SUP9 mainly include tensile strength, yield strength, elongation, impact toughness, etc. Its tensile strength is up to 1200MPa, yield strength up to 1120MPa, elongation is 12%, and impact toughness is 55J cm2.
3. Production and processing of various profiles
1.Production and processing of plates:SUP9 sheet can be hot-rolled or cold-rolled, hot-rolled sheet has a rough surface, cold-rolled sheet has a smooth surface, and can be used to make various springs.
2.Production and processing of round bars:SUP9 round bars can be hot-rolled, cold-drawn and forged and can be used to make a wide range of springs.
3.Production and processing of forgings:SUP9 forgings can be hot-forged to manufacture springs of various shapes.
4.Production and processing of seamless pipes:SUP9 seamless tubes can be hot-rolled and cold-drawn and can be used to manufacture a wide range of springs.
5.Production and processing of forging rings:The SUP9 forging ring can be hot-forged to manufacture springs of various shapes.
4. Experimental methods and conclusions
1.Experimental Methods:Tensile test, hardness test, impact test, etc. are carried out on SUP9 to obtain its mechanical property data.
2.Conclusion:SUP9 has excellent elasticity and fatigue life, and is suitable for manufacturing a wide range of springs and welded structures. Its tensile strength, yield strength, elongation and impact toughness are all in the excellent range.
5. The difference between casting and forging, and the smelting process
1.Difference Between Casting and Forging:Casting is the process of pouring molten metal into a mold to form the desired shape, which is suitable for manufacturing parts with complex shapes; Forging is the process of transforming a metal blank under pressure into the desired shape, which is suitable for manufacturing large quantities of parts of the same shape.
2.Smelting process:There are two main smelting processes of SUP9: electroslag and electric furnace. The electroslag furnace uses an electric arc to melt the impurities in the graphite electrode and molten steel, and discharges the impurities through electromagnetic force; In an electric furnace, pig iron, scrap and additives are smelted in the furnace to produce the required molten steel.
6. How to cold roll, hot roll and cold draw? How about electroslag and electric furnaces?
1.Cold rolled:The SUP9 plate is put into the cold rolling mill, and after many rolls and stretching, the surface of the plate can be smoothed and the size is more accurate.
2.Hot rolled:Heating the SUP9 plate to a certain temperature and putting it into a hot rolling mill for rolling and stretching can make the surface of the plate rough and the size more inaccurate.
3.Cold Draw:Put the SUP9 round bar into the cold drawing machine, after many times of stretching and rolling, the surface of the round bar can be smooth, and the size is more accurate.
4.Electroslag furnace:The SUP9 scrap and additives are placed in an electroslag furnace, which is heated by an electric arc to melt the impurities and discharge them through electromagnetic force to produce the required molten steel.
5.Electric stove:SUP9 pig iron, scrap and additives are placed in an electric furnace and smelted to produce the required molten steel.