Canadian Plastics

SPOTLIGHT: The Latest In Mold Steel

Canadian Plastics   

Overstating the importance of steel to the moldmaking industry is like overstating the importance of gin to a G&T--it can't be done. Here's a look at some recent offerings.

Overstating the importance of steel to the moldmaking industry is like overstating the importance of gin to a G&T–it can’t be done. Here’s a look at some recent offerings.


Bohler Uddeholm has developed M303 Extra (pictured), a stainless martensitic chromium steel, offering excellent toughness, corrosion and wear resistance. Characterized by improved machinability and polishability, the Extra M303 grade was developed for improved homogeneity ensuring good usage properties.

The grade is designed to give good polishability without having to be remelted, saving on cost for the alloy.


The homogeneity of M303’s chemistry yields a major advantage over 1.2316, in that no delta ferrite forms in the matrix, meaning that mechanical properties like fracture resistance are unaffected. M303 is pre-hardened to 32-36 HRC, and is primarily for prototyping and for short and medium production runs.

Bohler Uddeholm Canada (Mississauga, Ont.);;1-800-665-8335


With a delivered hardness up to 38 HRC, the new ThruHard Supreme from Buderus Specialty Steels is designed to satisfy the growing need for molds with larger dimensions.

Available in regular grade 31 HRC and in HighHard grade 36 HRC, the new steel offers good product quality due to etch grain and mirror finish reliability, and high gloss polishability in the HighHard grade for applications such as producing transparent parts.

The steel can significantly increase mold service life due to uniform hardness through to the core, even with the largest dimensions.

Also, high strength, good toughness and low internal stress provide resistance to costly tool damage.

Buderus Specialty Steels/Dan Coll Agency (Windsor, Ont.); 519-562-6651


Two new grades of Toolox prehardened tool steel plates are now available from Hasco America Inc.

These low-carbon steels offer low residual stresses, which helps achieve nearly distortion-free machining, and their high cleanliness (close to ESR levels) facilitates polishing and etching.

They need no heat treatment and their high-heat tolerance of 1,094 F (590C) allows them to be gas nitrided and PVD coated.

Toolox 33 is prehardened to 29 HRC and tempered, but can still be machined more easily than competing steels. Toolox 44 is prehardened to 45 HRC with the same hardness throughout.

Hasco Canada Inc. (Toronto);;1-800-387-9609


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