High Carbon Spring Quenched and Tempered Steel Strip
High carbon spring quenched and tempered steel strip offers superior hardness, toughness, tensile strength and spring properties. They have a fine tempered Martensite microstructure, and can be used for a variety of applications such as valve plates for compressors, clock springs, clutches, brake components and horn diaphragms.
Edge dressing is possible. This increases handling safety and can protect coverings such as plastics on the finished product.
Hardening
Hardening is a thermal process that strengthens cold rolled strip through a controlled heating and cooling process. This allows for better mechanical properties and flatness, as well as a stronger, more durable product.
The steel strip is heated to above the critical transformation High carbon spring quenched and tempered steel strip temperature for its grade and then rapidly cooled. This results in the formation of martensite and ferrite within the microstructure of the strip material. The resulting brittle material is called tempered spring steel.
It is important to use the right quenching medium for your specific steel grade. For example, some steel alloys require oil quenching to achieve the desired hardness and spring properties. For this reason, it’s important to consult with a metallurgical expert or your steel manufacturer for recommendations on how to properly heat treat your product.
Once your steel strip is sufficiently tempered, you can perform quality control tests to ensure that it meets the desired hardness and tensile strength specifications. These tests can include hardness testing and tensile testing, among others.
The tempering process involves reheating the strip to a lower temperature and then holding it at that temperature for a period of time. The reheating is typically done in an inert atmosphere to avoid oxidation. The tempered strip is then ready to be used in a variety of applications. Typical uses of this type of steel include valve plates and flapper valves for compressor units, clock springs, clutch assembly, industrial knives, etc.
Quenching
We use the quenching process to transform the austenitic microstructure of our carbon steel strip into martensite, which is hard and durable. This makes the steel much easier to work and weld. The process also helps to relieve internal stresses in the metal. After quenching the metal, we must temper it to make it ductile.
When quenching, the metal is submerged into a cool fluid or gas to rapidly reduce its temperature. We offer several different quenching processes based on your requirements. Fresh water quenching is a common option and works well for many applications. However, it can cause distortions in the metal, which must be further treated by metallurgy techniques to eliminate.
For more specific applications, we can use specialized quenching oils that are specially formulated to cool metals quickly. This is a safe and effective method for high-performance alloys and low-carbon steels.
For a passive cooling process, we can also allow the metal to slowly cool in air. This is slower than other quenching media, but it offers a cost-effective option that’s environmentally sustainable. We can also use forced air quenching, which involves forcing pressurized air through the metal to speed up the cooling process.
Annealing
The annealing process is a controlled heating of most metals and alloys above their recrystallization temperature. This allows new grains to form and existing ones to reorient, softening the metal and making it easier to work with. It also relieves internal stresses caused by forming and working the metal, making it more ductile and less brittle.
This process, when performed properly, produces a material with a balanced ductility and toughness suitable for most engineering applications. It is able to handle shock resistance and bending without being permanently deformed, with the high tensile strength, low elongation at fracture, and good fatigue strength characteristics required for use in critical engineering applications such as clock springs, brake pads, horn diaphragms and brackets and industrial knives.
The final stage of heat treatment for steel is tempering, which is a combination of controlled heating and cooling processes. The tempering furnace reheats the martensite-hardened steel to temperatures below its austenitizing temperature, which softens it and causes the existing grain structure to reorient. It is important to carefully control the tempering process because it determines the hardness of the finished product. By controlling the tempering temperature, a wide range of hardness levels can be achieved from an individual steel strip product. By applying this rigorous tempering process, we are able to produce high quality, spring-tempered steel strips that offer excellent strength and ductility, with good impact and bending resistance properties.
Tempering
After hardening the steel strip is in a very hard – but brittle – condition, which requires tempering. This involves reheating the steel to a lower temperature, holding it there for a specified period of Tinplate Steel Coil / Sheet time and then cooling it again. This reduces the hardness and improves the toughness of the strip.
During tempering the unstable martensite decomposes to form ferrite and stable cementite, and the tempered martensite also appears as acicular or lenticular microstructures (needle-like or lens-shaped). This allows the steel to be worked with ease and makes it more resistant to shock loads.
Tempering also relieves internal stresses caused by quenching, which would otherwise lead to cracking or breaking of the strip. High quality tempered spring steels have excellent fatigue strength and can withstand repeated cycles of alternating tension and compression.
The process of hardening and tempering develops an optimum combination of strength, toughness and flatness in a engineering steel strip, allowing components to be made from thinner material. This in turn leads to savings in both weight and cost.
voestalpine Precision Strip WI in Pleasant Priarie has state-of-the-art continuous heat-treating furnaces, designed and built by Austrian manufacturer EBNER, the world leader in this field. The furnaces can process a wide range of gauges and a full spectrum of spring steels from low carbon to very high alloyed grades, with an average yield strength above 1200 n/mm2. This enables a vast variety of application.
