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Steel Grade Corrosion Resistant Toolholder

Bohler-Uddeholm has introduced Uddeholm Idun from the Swedish manufacturer Uddeholm AB. "With this revolutionizing grade, we offer safe and reliable finished toolholders for indexable inserts," said a company spokesperson. "This pre-hardened and stainless holder grade transforms production to a one-stop shop where heat treatment and coatings will no longer be necessary."

"In recent years there has been a trend towards machining more and more tools in the hardened condition to both meet the market demand on shorter delivery times, and also save both time and money on heat treatment.

The next natural step in order to further decrease the production time is to get rid of costly and time demanding coatings. "Uddeholm Idun is offering the first patented corrosion resistant toolholder grade on the market," said the spokesperson.

Test Results

Uddeholm Idun has undergone comparison tests in a salt spray chamber according to SS-EN ISO 9227 using 0.1M salt solution at 35 °C (95 °F) for 3.5 hours.

In the test three samples were used. One standard milling cutter where the nickel coating had been ground off; one milling cutter with an intact nickel coating; and one milling cutter made from Uddeholm Idun. "After 3.5 hours, the ground off milling cutter was heavily corroded; on the nickel coated holder we found out that the nickel coating protected the holder to some extent, but corrosion spots had already started to appear. Uddeholm Idun showed less corrosion than the nickel coated cutter which proves that the corrosion resistance is at least in parity with nickel coating or better," said the spokesperson.

Uddeholm Idun is pre-hardened to 42-46 HRC, a hardness range optimal for milling cutters. Uddeholm Idun, which is an ESR (Electro Slag Remelted) steel, has a uniform microstructure with small carbides in a martensitic matrix. The hardness is consistent from the surface to the center. Although delivered in the hardened condition, Uddeholm Idun still offers a good machinability and can be induction hardened to 56 HRC on the surface if wear resistance needs to be improved locally.

"Uddeholm Idun has a much better softening resistance than standard P20 type materials at a constant temperature of 450 °C (842 °F) and keeps a high hardness at 500 °C (932 °F) for a long time," said the spokesperson. Specimens have been exposed for high temperatures up to 100 hours.

"When producing milling cutters in the hardened condition by turning, milling and/or drilling, compressive positive stresses are normally introduced on the surface. Compressive stresses can also be introduced by e.g. shot peening. Uddeholm Idun has very good stress relaxation properties that ensure that these stresses are kept high up to relatively high temperatures," said the spokesperson.

For more information contact:

Bohler Uddeholm Corporation

2505 Millennium Drive

Elgin, IL 60124


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