Writer： admin Time：2019-09-18 03:47:07 Browse：282℃
Customer background
A large steel group in Russia has an annual production capacity of over 12 million tons. The key equipment of its hot rolling production line, such as support rollers and work rollers, has been subjected to high temperatures (800-1200 ℃), heavy loads (rolling force of 2000-5000 tons), and erosion of iron oxide scales for a long time, resulting in frequent problems such as roller surface wear, peeling, and cracking. The traditional welding repair process has a large thermal deformation (deformation exceeding 2mm) and low bonding strength (≤ 200MPa), resulting in a roller life of less than 3 months after repair, which seriously restricts the continuity and cost control of the production line.
Customer requirements
1. Millimeter level repair accuracy: The roller surface repair needs to ensure a contour accuracy of ≤ 0.1mm to avoid surface defects on the rolled material;
2. Extreme working condition adaptation: The cladding layer should have high hardness (HRC ≥ 55), resistance to thermal fatigue (cyclic temperature shock>500 times), and oxidation resistance;
3. Cost efficiency optimization: The cost of a single repair should be controlled within 30% of the purchase price of the roller body, and the repair cycle should be shortened to within 72 hours.
Our solution
We have customized a 6000W fiber laser cladding system for it, integrating a six axis FANUC robot and a rotary table, and achieved breakthroughs through the following innovative solutions:
1. Using nickel based alloy as a base to enhance the metallurgical bonding strength with the roller substrate (55CrMo steel) (≥ 400MPa); The second layer is made of tungsten carbide, with a surface hardness of HRC58-62 and a wear resistance four times higher than the original roller body;
2. We provide customers with recommendations on power and powder delivery rate, optimizing the overlap rate to 35%, ensuring a thickness uniformity deviation of ≤± 0.05mm in the cladding layer, and ensuring zero porosity and no crack defects in the cladding layer;
3. CNC grinding machine integrated processing, surface roughness Ra ≤ 0.4 μ m, meets the requirements of rolling high smoothness plates.
Implementation results
1. Performance breakthrough: After repair, the service life of the rolling mill has been extended from 90 days to 280 days, and the steel passing capacity of a single roll has exceeded 150000 tons, which is 300% higher than traditional welding;
2. Cost optimization: The cost of a single repair is only 25% of the purchase price of the new roller, saving over 1.2 million US dollars in spare parts costs annually;
3. Efficiency improvement: The entire repair cycle has been compressed to 60 hours (including cooling and machining), reducing production line downtime by 70%;
4. Environmental benefits: Reduce metal powder waste by 40%, reduce annual carbon dioxide emissions by 150 tons, and comply with the requirements of the EU Carbon Border Tax (CBAM).
Customer reviews
This 6000W equipment has completely changed our equipment maintenance system. The surface hardness uniformity of the repaired rolling mill reached ± 1.5HRC, and the qualified rate of rolling plate shape increased from 92% to 98.5%, becoming a benchmark case for the group's global factories. ”——Dmitiry， Equipment Supervisor