The product development work at Boxholm Stål AB is aimed at increasing the refinement rate and refinement possibilities for the company’s products and helping the customers lower their costs for finished products and shorten overall lead-times.

 

This process involves: new products, quality and process development and investments conducted in a forum called Produktråd (Product council), which is led by our product development manager and includes representatives of the CEO, quality manager, sales and process development departments. The product council discusses and prepares matters of strategic development for decision-making by the management group.

 

The product development projects are conducted in cross-functional groups, either with full internal representation or with the external participation of raw material suppliers, customers, trade organisations and universities. Here are just some examples of our projects: (Swedish Institute for Corrosion and Metal Research)

 

 

 

 

Boxholm Stål AB has in 2004 been running the ‘Effect of reworking on the machinability of a low alloyed steel’ in cooperation with KIMAB (Swedish Institute for Corrosion and Metal research). The aim of the project was to investigate the effect of cold drawing on machinability during longitudal turning. Heat-rolled bars (Ø38 mm) in perlitic – ferritic steel Ck45Pb were cold drawn to diameters of 37, 36 and 35 mm, which is a reduction grade of 8.5%, 13.4% and 18.8% respectively. The steel’s mechanical properties including hardness were enhanced by cold drawing, but the effect tapers off at a reduction grade > 10%. After a microstructure examination and strength-testing, a machinability test longitudal turning was performed, with the following results:

Cutting speed	300m/min
Cutting depth	1 mm
Feed	0,3 mm/varv
Tooling	Seco TP1000 SCMT120408-F2

 

 

Cutting force and tool wear were measured during the course of the test. Machinability tests showed a clear improvement (by around 30%) in machinability with the cold drawn material. The best results were achieved with low and high reduction values. It appeared that the material with medium reduction properties had a different structure, presumably depending on being cooled differently after rolling and did therefore not achieve the expected machinability results. The results are shown in the diagram below:

 

The project reached the conclusion that cold drawing with a reduction of around 10% is a good way of enhancing machinability. For more information about the project, please contact Mikael Nissle, Boxholm Stål AB or professor Hariharan Chandrasekaran, KIMAB.