US1685602A - Mode of producing wrought iron with increased tensile properties - Google Patents

Description

Patented Sept. 25, 1928.

GEOBG GUDE GEDDA, F SURAHAMME R, SWEDEN.

MODE 0! PRODUCING WROUGH'I. IRON WITH INCREASEDTENSILE PROPERTIES.

1T0 Drawing. Application filedDecember 9, 1925, Serial No. 74,408, and in Sweden July 17, 1925.

Wrought iron processes heretofore practiced, such for example as the triple melting- 5 and the puddlmg processes, have to a large extent been superseded b the ingot steel production, duepartly to t fact that this has proven to be cheaper, and partly because it results in a product having its composition In so altered as to increase the tensile properties thereof.

To substitute the ingot iron for the Wrought. iron has, however, been impossible for certain purposes. This is the case, when '5 the welding capacity and the fibrous structure, qualities which are characteristic of the wrought iron, are of a decisive importance. The production of a wrought iron with its usual characteristic qualities, but

.20 with an improved tensile strength, has long been sought. For this purpose an incomplete fining away of coal or manganese has been proposedbut by this process the 'weld-' ing capacity is disadvantageously afl'ected and the process is very unreliable, also. It

has also been proposed to use a pig-iron with a specially high percentage of phosphorous;

in this case the whole phosphoric percentage is met with in the wrought iron, which causes an improved tensile strength of the product, but also a greater brittleness and a greater. unreliability. Experiments have been made with cold rolling, but because of its unreliableness this mode is not practical,

at least when important construct-ion materials are concerned. In these and other cases it has been possible to increase the elastic limit and to increase the maximum tensile strength, but the contraction and the impact capacities have, on the other hand, always been decreased.

The problem ofincreasing the maximum tensile strength of the wrought iron, and also increasing its elastic limit, without a simultaneous and considerable reduction .of' its welding capacity, as well as the impact and contraction capacities of the material, is

solved by the present invention.

I have discovered that this may be attained b an alloyin of the wrought iron with nic el. It may e accomplished in vapact test 12-14 kg. cm./mm. the use of the rious ways. For example,as fining material I may use a pig-iron, that previously has been a loyed with nickel, for instance by such means, that the nickel as pure metal or as an alloy has been put in the charge used in the pig-iron production. The nickel may also be put in by such means, that the nickel, or a nickeliferous material, is placed; in the finery or, it is possible by the use of nickeliferous iron in such a way to increase the quantity of nickel. Nickel being a metal with considerably less aflinity' for oxygen than the iron, practicall the whole quan tity of nickel used will orm a part of the refined iron. In the slag there will only be traces of nickel. Y a

A Lancashire bloom produced by the invention and containing 0,03% C, 0,01% Si, 0,07% Mn, 0,006% s, 0,021% P and 3,57% Ni has, by analysis, 1proved to have a maximum tensile strengti of 38,5 kg./mm; an elastic limit of 30-31 kg./mm. a contraction of about-75% and an impact test as per Charpy of about 17 kg.cm./mm. Lancashire iron of the composition mentioned above, without the nickel, has a maximum tensile strength of about 30 kg'n/mmf and an elastic limit of about 17 kg./mm. Thus the nickel has effected a material increase in the maximum tensile strength and also in the elastic limit of the product. And as for usual Lancashire iron the contraction seldom reaches more than 60-70% and the imnickel has also eflected a considerable increase in thesequantities of the product.

In the problem in question as in man other respects cobalt has proved to havequa ities, which are similar to those of the nickel. Thence it is possible to carry out the present invention with cobalt entirely or partly substituted for the nickel.

For some purposes it may be convenient to alloy with-the wrought iron besides the nickel or the cobalt also a small quantity of copper. To the other good 'qualities the use of copper adds an increased resistance against rust.

-I claim as my invention:

1. The process of manufa'cturin wrought iron conslsting in heating nickeli erous pig iron and puddling the same in aimannm to produce a wrought iron to increase the usual tensile strength and elastic limit thereof Without decreasing its Welding and contracv t1on capacities.

2. The 'process of manufacturing Wrought iron consisting in adding a predetermined amount of nickel to ordinary pig iron and then heating the. mass and so puddling the same as to produce a Wrought iron ofincreased tensile strength and elastic limit Without decreasing its Welding and contraction capacities.

In Witness whereof, I have hereunto signed my name. 7

. sEoRG GUDE GEDDA.