Influence of Process Parameters on Stress Characteristics of Wear-resistant Steel in Cold Rolling

    
    The cold rolling of wear-resistant steels, such as martensitic stainless steels or high-strength, low-alloy steel, is an important manufacturing process for improving the mechanical properties of materials. During cold rolling, as the material passes through the rolls, plastic deformation occurs due to compression. This compressive deformation results in elevated stresses on the material, which can lead to premature failure if not properly addressed. Therefore, it is important to understand how different process parameters can affect the stress characteristics of the material during cold rolling.
    
    Roll loading is the most important factor in controlling the stress levels in the material during cold rolling. High roll loading creates high local compressive stresses at the contact region, depositing a large amount of strain energy in the material. This increase in strain energy can have a significant impact on stress distribution and the mechanical properties of the material. Additionally, the angle of the top roll relative to the bottom roll can influence the distribution of stresses in the material. A larger angle between the two rolls, also known as back-up angle, will cause the material to spread out over a larger area, resulting in a lower level of stress in the material.
    
    Another key parameter in the cold rolling of wear-resistant steels is the ole-entry speed. The entry speed of the roll will determine how much strain energy is applied to the material, and thus how much stress is generated. Generally, lower entry speeds will result in lower stress levels in the material. However, if the entry speed is too low, it can also cause premature failure due to inadequate deformation.
    
    Finally, the roll material itself can affect the stress characteristics of the material during cold rolling. Different roll materials can present different surface topographies, which then can generate different contact geometries between the roll and the work piece. For example, hard-faced rolls, which have a hard surface with small randomly distributed bumps and ridges, can lead to greater stress accumulation in the material due to the increased friction at the contact surfaces.
    
    In order to understand the influence of different process parameters on the stress characteristics of wear-resistant steels during cold rolling, a series of experimental studies were conducted. The experimental results showed that the roll loading, ole-entry speed and roll material have a significant effect on the stress distribution in the material.
    
    At low roll loading, a lower ole-entry speed was found to result in lower stresses in the material. On the other hand, at high roll loading, a higher ole-entry speed was found to result in higher levels of stress in the material. Additionally, the use of hard-faced rolls resulted in greater stresses in the material due to the increased friction at the contact surfaces.
    
    Fig: Schematic of Stress Characteristics of Wear-Resistant Steel in Cold Rolling
    
    As can be seen, different process parameters in the cold rolling of wear-resistant steels can have a significant effect on the stress characteristics of the material. To ensure satisfactory performance of the materials in use, it is important to consider the influence of each process parameter when selecting the processing conditions.

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