Mitutoyo Surface Tester aids Tata Steel Quality
With operations in 26 countries and commercial offices in over 35 countries, Tata Steel is one of the world’s most geographically diversified steel producers. Tata Steel serves a wide variety of demanding global markets and is a leading manufacturer of high quality packaging steels. Tata Steel Packaging based in Llanelli, South Wales is a supplier of light gauge steel for packaging and non-packaging applications. The Llanelli plant produces an extensive range of high-quality packaging steels in various widths, gauges and with an assortment of applied coatings, the range includes tinplate, tin-free steels.
High-quality roll surface texture is an essential requirement of good steel strip surface quality and is a major factor in the success of the Tata Steel Packaging’s rolling process. The surface texture imparted by the work roll to the strip has a major influence on the behaviour of the sheet during subsequent pressing, painting and coating operations.
Given the extremely harsh conditions steel rolls are subject to when being processed, prolonged use can have a detrimental effect on their surface texture characteristics. When in service, regular surface finish measurements with the use of the company’s Mitutoyo’s Surftest SJ-210 surface testers enables Tata Steel Packaging’s rolls to be inspected and withdrawn from service before they reach the bottom limit of their surface finish parameters, and to be replaced by newly refurbished rolls. The worn rolls are then precisely reground and again inspected with a Surftest SJ-210, to ensure that the optimum surface condition of each roll is achieved. Given the minimum stock removed in each grinding process, Tata Llanelli’s rolls are able to go through this in-service/grinding cycle on multiple occasions.
A range of large capacity, advanced CNC grinders operated by skilled personnel ensure the best possible surface finish results. Tata Steel Packaging’s impressive machines have capacities enabling workpieces from 3 tonne – 25 tonne in weight and up to 3 meters long to be accommodated. As well as other advanced features, each machine has an on-board automatic crack detection system.
Tata Steel Llanelli, Roll Shop Section Leader, Kevin Thomas explained. “Although Tata packaging steels meet all of the strength, surface finish and forming properties of our customers and are designed to suit their production processes and end-uses, we are constantly searching for ways to further develop our production and quality control systems. Precision grinding is a critical aspect of our roll refurbishment texturing process and the grinding process must be completed in a very precise manner to achieve the high quality finish needed. With the aim of advancing our existing roll and strip surface finish inspection routines, some months ago we searched the market for a surface finish tester that would improve on the features of the instruments we were then using. We found the answer in the Surftest SJ-210 from Mitutoyo.
“Before we made our choice, we performed in-depth Gauge R&R studies to determine the accuracy and repeatability of the Mitutoyo tester when used by our operators. We also compared factors such as the Surftest SJ-210’s ease of use, robustness and battery life, against the instruments we were currently using. The Mitutoyo Surftest SJ-210, scored higher in all areas. Now in constant use, given the size of our plant, it helps that our multiple Mitutoyo portable surface roughness testers are able to operate independently of mains power and to take accurate surface measurements on any part of our rolls when in use, and also on our rolls when being reground. In addition, the instruments are in constant use inspecting the surface quality of the strip that we produce.
“As part of our stringent quality regime, to ensure that our Mitutoyo Surftest SJ-210’s remain accurate, we calibrate each of them on a daily basis against a calibrated and traceable master. Although we only use Ra and Rz surface roughness parameters, we regard our Surftest SJ-210s as future-proof as, if ever we need to test in other parameters, our Mitutoyo instruments are able to operate in a wide range surface roughness parameters.”
Complying with the relevant industry standards applying to surface texture measurement, Mitutoyo’s Surftest SJ-210 is a user-friendly surface roughness tester designed as a robust, handheld tool that can be easily carried and used on site. A simple key layout provides users with easy access to the Surftest SJ-210’s multiple functions, whilst a high visibility, colour-graphic LCD with a backlight provides excellent readability in all lighting conditions and displays assessed profiles and graphical data. The Surftest SJ-210 boasts advanced data storage capabilities, up to 10 setups and one measured profile can be stored in the unit’s internal memory. An optional memory card can be used to further expand the tester’s memory and to enable the storage of large numbers of measured profiles and setups. If required, data can be transferred to and from a computer via a high-speed USB interface.
In addition to calculation results, the compact instrument can display sectional calculation results and assessed profiles, load curves and amplitude distribution curves. Access to each feature can be password-protected, which prevents unintended operation and enables settings to be protected.