Premium Steel Strip Products and Production Process

Guangzhou Jiaxiao Material Technology Co., Ltée. is a leading supplier of Premium high carbon steel strips, alloy steel strips, et bandes d'acier inoxydable in heat treatment methods – hardening and tempering conditions and cold rolled annealing conditions. The company covers an area of 25,000 square meters and has over 100 employees, including senior technical staff and 30 mid-level technical staff. It is equipped with a series of advanced facilities such as acid washing, laminage à froid, recuit, cutting slitting, trempe et revenu, mechanical polishing, flattening machine, edge treatment, etc., ensuring that the products meet high standards in terms of thickness, width, flatness tolerance, decambering, deburring, and round edging for safety applications, and fulfilling customers’ customized requirements.

Product Business Scope

1. Diverse Steel Products: The company supplies a variety of Premium Steel Strip products, including high carbon spring steel strips like C67S, C70S, C75S, C80S, C85S, C90S, C95S, medium carbon steel strips such as C45S, C50S, C55S, C60S, alloy steel strips including 50CrV4, 51CrV4, 60Si2Mn, 50CrNiMoV, AISI420 stainless steel strips, 75Cr1, 75Ni8, D6A, X32, M42, 68CrNiMo steel strips, and S35E, S355MC, 16MnCr5, S550MC steel strips, etc. The annual supply capacity is approximately 15,000 tonnes.
2. Strict Raw Material Procurement: The company purchases first-class raw materials from ISO-certified state-owned enterprises to ensure excellent product quality.

Production Process and Technological Features

1. Acid Washing: Raw materials (hot rolled steel coils) are purchased from reputable hot rolling factories and are acid washed before cold rolling to remove the oxide layer on the steel surface. The acid washing process uses acid to clean and etch the surface of the steel coil, removing the oxide scale with a thickness generally ranging from 5 to 20um that is insoluble in water, thereby improving the steel surface quality.
2. Cold Rolling: The company uses cold rolling equipment to reduce the thickness of the hot rolled steel coils to the required size with precise dimensional tolerances. For example, the 4-high reversing cold rolling mill is mainly used to produce thin steel strips with a thickness ranging from 0.08mm to 0.15mm and has excellent tolerance control capabilities. It can achieve high-quality rolling technology standards, ensuring thinner steel strip thickness and meeting process reliability and maintenance requirements. At the same time, it has a deformation-optimized housing geometry, resulting in a flat strip surface.
3. Leveling: The leveling machine is used to eliminate shape defects (such as curvature or twist) in the coiled material before heat treatment, ensuring that the material properties and product standards meet customer requirements. By stretching the coiled sheet steel beyond its yield point, the material achieves perfect flatness and relatively low internal stress.

Annealing (Cold Rolled Annealed Steel Strip)

1. Process and Product Types: The company mainly produces Premium bright annealed steel strips and spheroidized steel strips. Bright annealing involves heating the steel coil to a high temperature in a confined space of the annealing furnace and then slowly cooling it, resulting in a bright surface without decarburization. Spheroidization is achieved by holding the steel at temperatures near the lower critical point for a prolonged period or through cyclic heating and subsequent cooling near these temperatures. The process can be accelerated by prior deformation or hardening. Spheroidized steel strips are suitable for various applications requiring maximum cold forming.
2. Product Specifications and Applications: The Premium annealed steel strips have a thickness range of 0.1mm to 5.00mm, a width range of 2mm to 1200mm, a maximum hardness of 180HV, and the surface can be polished. The edges can be milled, slit, or sheared. They are mainly used for products that require severe bending and shaping to very high hardness before heat treatment, such as springs, washers, spacers, clips, pins, inserts, shoe shanks, toe caps, auto components, auto clutches, etc.

Quenching and Tempering (Hardened and Tempered Steel Strip)

1. Process and Performance Characteristics: We conduct a thermal process called quenching and tempering for the Premium steel strip. Firstly, we heat the steel strip above the critical transformation temperature for its specific grade and then rapidly cool it to harden. However, at this stage, the Premium steel strip is extremely brittle, so it needs further treatment in the tempering process. We reheat it to a lower temperature and maintain it at that temperature for a certain period. This process is carried out in an inert atmosphere to prevent oxidation. The final steel strip obtains a high degree of toughness and excellent spring properties. The steel strip has a thickness ranging from 0.1mm to 5.00mm, a width from 2mm to 500mm, and a hardness of 30 – 55HRC. Its edges can be slit, rounded, or squared, and the surface can be natural, blue, yellow, white, or polished.
2. Application Fields: It is widely used in products such as rolling shutter door springs, band saw blades, scrapers, trowels, putty knives, shoe insoles, knives, various flat springs, etc., which do not require severe bending. For example, the company’s steel strip for shutter springs is of high quality and widely exported around the world. It is suitable for various weights and specifications of rolling shutter doors, accurately matching spring sizes and quantities.

Other Production Processes

1. Slitting and Length Cutting: After cold rolling the master coils, we slit them to the required narrow width before annealing or hardening & tempering, or cut them into sheets of the length as per the user’s request. We achieve slitting by passing the coiled strip through a set of rotating knives to continuously shear the wide coil to the exact width needed for narrower coils. The cutting length can be 1m, 2m, 3m, 4m, 5m, etc.
2. Polishing: We can polish the steel strip to improve its surface quality and meet customers’ different surface finish requirements.

Quality Control and Product Packaging

1. Strict Inspection: The company uses laboratory equipment to conduct strict inspections on the Premium steel strip in terms of material composition, size, hardness, tensile strength, etc., ensuring that the products meet customer requirements. The inspection items include material strength testing, metallurgical structure inspection, sample making strength testing, chemical composition analysis, hardness testing (Rockwell, Brinell, Vickers), and flatness testing.
2. Packaging and Transportation: we first lightly oil each coil, then wrap it with plastic film and anti-rust paper, and finally load it into a 20 – foot container to ensure the product quality during sea transportation.

With rich industry experience, advanced equipment, and a strict quality control system, Guangzhou Jiaxiao Material Technology Co., Ltée. is committed to providing high-quality steel strip products for numerous industries and continuously pursues product quality improvement and cost optimization to meet the growing needs of customers.