US2157146A - Scale-resisting steel alloy - Google Patents

Description

Patented May 9, 1939 UNETD STATES OFFIC' SCALE-RESISTENG STEEL ALLQY of Germany Ne Drawing. Application November 7, 1030, Se-

rialNc. 100,673. in Germany May it, 1030 1 Claim.

this character, aside from being scale-resisting have the advantage that they can be easily worked and machined and do not become brittle when used at high temperatures.

The present invention is based on. the recognition that the cost of producing such alloys, without impairing the above-mentioned essential characteristics, can be materially reduced by either entirely omitting the content of the costly chromium, or at least reducing its content considerably below that suggested in the prior art. With the reduction of the chromium content the carbon content should also be reduced and be limited to a range of from 0.01 to 0.30%.

According to my invention, I propose a scaleresisting steel alloy of the following composition:

Per cent Carbon 0.01 0.30

Manganese 15.00-30.00

Silicon over 3.00-10.00

chromium may be added. Furthermore, if certain additional characteristics of the alloy are desired, small amounts of molybdenum, or tungsten, or titanium, or vanadium, or tantalum, may be added, either alone or a combination of these 5 elements, but in general such additions should not exceed 2% of the alloy. For instance, if it is desired to improve the strength at high temperatures of the article made of my novel alloy, molybdenum or tungsten or both should be added withw in the above mentioned percentage. If brittleness is to be resisted, titanium, vanadium or tantalum may be added.

The class of articles or tools which are particularly improved when made of my novel alloy are 15 specifically those used in annealing, hardening, and similar high temperature processes, such as annealing boxes or pots, cementing boxes or pots, case-hardening boxes or pots, raking hooks or bars. Further, heat-treating furnace construcat tion elements such as lifting beams, rails for automatic furnaces, grate bars for enameliug ovens and similar objects, in all of which cases the equipment when exposed to high temperatures shouldnot only retain its mechanical 85 strength but should resist scaling.

I claim:

A steel to be exposed to high temperatures in performing metallurgical or other thermal operations, consisting of 0.01% to 0.30% carbon, 15.0% to 30.0% manganese, over 3.0% to 10.0% silicon, the remainder iron and customary traces of impurities, and characterized by elevated scaleresistency. s

GERHARD RIEDRICH. 88