US2576229A - Steel for tools operating at elevated temperatures - Google Patents

Description

Patentecl Nov. 27, 2951 1 STEEIlF OR 'rooLs OPERATING A ELEVATED TEMPERATURES Helmut Krainer, Kapfenberg'fliustria, assignor to Gebr. Biihler, & Co. 'Aktiengesellschaft,

- Vienna, Austria No Drawing. Application February 27,1948; Se- 1 rial No. 11,873. .In Germany March 12, 1941 l Section 1 Public Law 69!),Aug1ist s, 1946 Patent expires March 12, 1961 The use of alloy steel containing tungsten, chromium, molybdenum and vanadium for tools operating at elevated temperatures is commonly known. Steel containing 2.5% chromium, 9% tungsten and 0.5% vanadium has been used mostly. In cases where the above type of steel is used for high duty tools the total of the alloying element tungsten, molybdenum and vanadium amounts always to more than 5%, the bulk consisting of metals in short supply viz. tungsten and molybdenum.

Hence effort has been made to develop alloy suitable for high duty tools intended for operation at elevated temperatures havin a restricted content of tungsten and molybdenum. Their performance was, however, found to be considered poorer even in the case of insignificant reductions of the amounts of alloying metals added.

These alloy-saving materials comprise the chromium, molybdenum, tungsten and vanadium alloyed steel with even lower percentage of alloying metals as compared with those concerned by present invention.

Extended experients have proved the possibility of obtaining not only equal performance of the tools but even better efiiciency in comparison to the well known 9% tungsten steel by suitable adjustment of the alloying elements tungsten, molybdenum and vanadium.

The composition of such alloys has to be within the range of 0.1-0.6% carbon, 0.5-2.0% chromium, 0.5-2% vanadium, 0.3-1.8% tungsten or 0.2-l.7% molybdenum, totaling not more than 2%. The percentage of tungsten plus molybdenum should not be less than half the vanadium percentage, at the same time not exceeding the 1.5-fo1d value of the vanadium content. The percentage of vanadium about equalling the total of tungsten plus molybdenum has been found especially advantageous. Tungsten or molybdenum alone may equally be used. The best results, however, are obtained by simultaneous alloying with about the same amounts of tungsten and molybdenum totallin approximately half the percentage of vanadium. The respective content of chromium is preferably chosen slightly exceeding the percentage of vanadium. The total of tungsten and vanadium present may, however, exceed the content of chromium.

Bearing in mind the above balance of the alloying element it is possible to produce steel with a considerably reduced consumption of alloying additions having a better performance as compared With the commonly known 9% tungsten alloyed steel.

5 Claims. (01. is- 126) Compositions within the following ranges have proved to be of special advantage for the use claimed by the present application. 0.2-0.6% carbon, 12% chromium, 0.6-1.4% vanadium, 0.3-0.7% tungsten and 0.3-0.7% molybdenum. Steel containing 0.47% carbon, 1.58% chromium, 0.88% vanadium, 0.48% tungsten and 0.42% molybdenum may be quoted as an example.

Dies for pressing of screws made of the latter steel were compared to a commonly used steel containing 2.5% chromium, 9% tungsten and 0.5% vanadium. Dies made from the steel cited above proved to be of three times as good performance as compared with a standard steel. Further improvement of the performance of the dies was obtained when 0.l-0.7% of titanium were added to steel described in the present invention. This surprising success could by no means be expected from the generally accepted effects of the alloying elements and was to be obtained solely by the mutual balance of the respective alloying elements discovered.

Considerable chromium and vanadium as domestic or easily obtainable alloying elements and bearing in mind the three-fold improvement of the performance as compared to the commonly known and hitherto used steel with 2.5% chromium, 9% tungsten and 0.5% vanadium, the reduced amount needed of the metals in short supply, tungsten and molybdenum is of considerable importance.

By the application of steel according to the present invention the consumption of tungsten and molybdenum is reduced by about 30 times provided the same performance is used as a basis of comparison.

The considerable technical progress involved is accentuated by the advantages both in engineering and economy resulting from the 3-fold life of the tools.

Iclaim:

1. A steel alloy for making hot-working tools, especially hot-working pressing dies, consisting essentially of 0.1% to 0.5% carbon; 0.5% to 2% chromium; 0.5% to 2% vanadium; 0.3% to 1.8% tungsten; 0.2% to 1.7% molybdenum; the total percentage of the tungsten and molybdenum contents not exceeding 2%; the remainder iron and incidental impurities.

2. A steel alloy for making hot-working tools, especially hot-working pressing dies, consisting essentially of 0.1% to 0.5% carbon; 0.5 to 2% chromium; 0.5% to 2% vanadium; 0.3% to 1.8% tungsten; 0.2% to 1.7% molybdenum: the total percentage of the tungsten and molybdenum conespecially hot-working pressing dies," consisting 3 r tents lying in the range from 0.5 times to 1.5 times the percentage of vanadium; the remainder iron and incidental impurities. I

3. A steel all'ny for. making hot+iworking tools;

essentially of 0.2% to 0.5% carbon:- 1% tc-2% lF chromium; 0.6% to 1.4% vanadium 0.3% to...

0.7% tungsten; 0.3% to 0.7% molybdenum; the... ,3 remainder substantially all iron and incidental 7 ,4 impurities. 2118;78231 5. The composition defined in claim 1 having an additional content of 0.1% to 0.7% of titanium.

, HELMUT .K AmER.

REFERENCESUITED The following references are of record in the file of this patent: V

' UNITED STATES PATENTS Name Date 7 Braid; Apr. 17, 1934 RIoyen Jan. 14, 1936 FOREIGN PATENTS f 1Country Date Great Britain 1 Apr. 28, 1932 Great Britain June 7, 1934 Germany Mar. 22, 1939 Switzerland May 16, 1940

Claims (1)

1. A STEEL ALLOY FOR MAKING HOT-WORKING TOOLS, ESPECIALLY HOT-WORKING PRESSING DIES, CONSISTING ESSENTIALLY OF 0.1% TO 0.5% CARBON; 0.5% TO 2% CHROMIUM; 0.5% TO 2% VANADIUM; 0.3% TO 1.8% TUNGSTEN; 0.2% TO 1.7% MOLYBDENUM; THE TOTAL PERCENTAGE OF THE TUNGSTEN AND MOLYBDENUM CONTENTS NOT EXCEEDING 2%; THE REMAINDER IRON AND INCIDENTAL IMPURITIES.