Quenched and Tempered Steel Plate
Construction and manufacturing equipment must withstand heavy loads, so the materials used need to be strong. To make iron-based alloys stronger and harder, they undergo a heat treatment known as quenching and tempering.
Quenching is when the metal gets heated to an extreme temperature and then rapidly cooled, usually in air, water, oil or inert gases like nitrogen. The process also involves tempering to reduce hardness and increase ductility.
Strength
Despite its high strength, quenched and tempered steel is relatively lightweight. This combination of strength and weight makes it ideal for construction and manufacturing equipment that must withstand heavy impact working conditions. Quenching and tempering strengthens materials like steel and iron based alloys, making them tougher and harder than their untreated counterparts. This is because the process of hardening (or quenching) involves intensely heating and then rapidly cooling the material, locking its components into place.
The process of quenching is tightly controlled, with the exact temperature, cooling substance and speed all determined by the type of metal being quenched. Quenched and tempered steel plate For example, low alloy steels typically need to be cooled in water, while unalloyed and low carbon steels can be quenched in oil. The precise cooling method is also important, as the steel can be distorted if it’s cooled too quickly.
After the initial cooling, the steel is tempered to reduce its hardness and make it more ductile. The exact temperature and duration of the tempering are again determined by the type of steel being tempered, but typically involve a range between 800 and 1,100 degrees Celsius. Tempering transforms the hard martensite into tempered bainite and lath martensite, and it can also help soften the ferrite that remains. OM and SEM micrographs of sub-surface, t/4 and t/2 positions of as-received quenched and tempered steel plate reveal variations in the size, shape and distribution of these tempered microstructures.
Toughness
Steel is extremely tough when it has undergone the quenching and tempering process. This process involves heating the material to a temperature above its critical point and then cooling it at a specific rate. During this process, various parameters such as the heating temperature, the type of coolant used and the cooling method must be closely monitored. All of these factors impact the final strength, hardness and toughness of the Steel.
After the quenching process, the steel is tempered in order to reduce some of its hardness and increase its ductility. The steel is heated for a set period of time at a temperature that falls between the critical point and 1,300degF, then allowed to cool again. This tempering process is crucial because it ensures that the steel is less brittle while maintaining its strength.
In addition to enhancing the toughness of the material, it also improves its resistance to wear and abrasion. This makes quenched and tempered steel ideal for use in machinery and equipment where greater abrasion resistance coupled with higher yield strength is necessary. This includes applications in mining, quarrying, earth moving and construction.
Durability
Quenched and tempered plate is often used in industrial applications such as earth moving, mining, construction and machinery. It offers greater abrasion resistance and higher yield strength compared to untempered steel. To achieve these benefits, the steel is subjected to a post-heat treatment process called quenching and tempering.
Alloy quenching and tempering is the most common method for strengthening steels. The process involves heating the steel to a high temperature, then quenching it in water or oil. This quick cooling allows the steel to become hard and tough, but it can also cause distortions in the material or internal stress.
In order to be quenched, steel must have a high enough carbon content to transform from body-centered cubic ferrite to face-centered austenite. It also needs to have a low melting point. To further ensure its suitability for quenching, the steel is soft annealed beforehand.
Once the steel is quenched, it becomes very hard, but brittle. Tempering, a heat treatment process, helps to reduce the hardness of the martensite while increasing its toughness by transforming it into softer phases. These softer phases can be formed by reheating the steel to a lower temperature, then cooling it in still air at a specific rate. The process can be done for a variety of reasons, from preventing the formation of cracks to achieving an optimal balance between strength and toughness.
Corrosion Resistance
Quenched and tempered steel plate is ideal for many applications that require high strength combined with good formability. This plate is easy to weld and machine, has excellent resistance to cracking due to stress and good corrosion resistance.
The first step in quenching is known as tempering, which reduces some of the hardness and increases ductility. In this process, the material is heated for a short period of time to a temperature that falls within the range of 400deg F and Tinplate Sheet Manufacturer 1,105deg F. It’s then cooled quickly in water, oil or air, depending on the desired result.
These processes have an effect on how the plate behaves in harsh environments, such as a salt spray chamber accelerated test. This test reveals the amount of corrosion damage to the steel and helps identify the type of corrosion. It also determines how long it takes for the first signs of corrosion to appear and how much mass loss the steel experiences during the test.
To study the impact of different heat treatments on corrosion resistance, we welded five AISI-304 plates and tested them in the salt spray chamber. The results showed that samples with a ferritic-pearlitic microstructure after normalizing had the lowest corrosion resistance. They also exhibited the highest resistance to fatigue. The corrosion resistance of the other samples improved with tempering, which reduced the tetragonal martensite lattice distortion and increased ductility.
