Lasers Solve Alignment Problems for Dofasco’s Casting Machines

Source: AISE Steel Technology

With lasers manufactured by Hamar Laser Instruments, innovative Canadian steelmaker Dofasco pioneered a continuous caster laser alignment system that achieved significant segment repair cost and time savings and resulted in increased segment life and improved as-cast slab quality. A subsidiary of ArcelorMittal, the world’s largest steel and mining company, Dofasco operates two continuous casting machines. High accuracy alignment is critical to meet tolerances of .002 in. (0.05 mm) and produce defect-free slabs.

When the first caster was brought on-line, Dofasco used OEM alignment stands and templates to align segment rolls to the passline and profile. This procedure, using feeler gauges, was very time consuming and a source of variability due to tradespeople’s fitting practices. It required 15 hours to complete and meeting tolerances was very difficult. Dofasco soon implemented an aligning procedure using an optical level. While an improvement, this method was also time consuming, needing 8 hours to complete, and meeting tolerances continued to be very difficult.

Within several years Dofasco had begun looking for a laser-based solution. The steelmaker turned to Hamar Laser, which implemented new alignment procedures using Hamar Laser’s L-740 Ultra-Precision Leveling Laser System, A-1530 Height Gage Target and a customized software package to align the caster segment rolls. The results achieved with the Hamar Laser system were dramatic.

Overall alignment time dropped by 87% and tolerances are met consistently. Repair times decreased more than 50%. The time required to rebuild segments was drastically reduced, and segments are now consistently rebuilt and installed with transitions well below the allowed standard of 0.12 inches. This reduced variability directly improved as-cast slab quality and segment life. Longitudinal and transverse cracking associated with misalignment was reduced to zero and segment life extended by more than 30%.

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