US2361672A - Steel wool - Google Patents

Description

Oct. 3l, 1944. H. wlNKLER STEEL WOOL Filed April 3, 1940 Siee Waal kmh-ny 0. maler Q35 Z gf' 11110.', KJV@ Z'jealame alli/7.

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Patented Oct. 3l, 1944 STEEL WOOL Louis H. Winkler, Bethlehem, Pa., assignor to l s Bethlehem Steel Company, a. corporation of Pennsylvania Application April 3, 19410, Serial No. 327,697 l s claims.

My inventionl relates to an improved composition of steel for the manufacture of steel wool. .This is made of relatively low carbon steel usually containing under 0.25 per cent carbon and rup to about 0.85 per cent manganese. .I have -found that increasing the manganese content to a range from 0.90 to 1.5 per cent results in a decided improvement. With the increased manganese content the ease in machiningrequired of this'grade of steel to avoid excessive wear of lthe wool cutting knives is maintained and even vincreased. At the same time thefbres formed are longer, tougher, stronger and more uniform in all these respects. What is most important 'is that the resultant wool possesses the combination of soft and resilient characteristics most usually desired. The fibres are uniformly long land toughand not short and fragile. Because of the better qualityqfthe wool produced, improved results are obtainedi in the' operations of steel wool making such as Winding, flattening, plaiting, compacting, forming skeins, braids, pads, etc.

The individual steel fibres also have greater toughness and resilience contributing to the desired efficient scouring or cutting action in service.

It is not certain exactly why the increased man- .'ganese content aids in producing the soft and resilient type of steel wool which is generally desired, and which the trade nds difficulty in making, as against the harsh type of steel wool which is seldom desired and which can readily be made by certain adjustments in the wool cutting machines. Manganese is generally considered to have a hardening effect on steel rather than a softening effect; however, it may be suggested that perhaps in the somewhat tougher and lharder higher manganese steel the fibres split off.

, more readily ahead of the cutting tool. Furthermore, I have observed that the higher manganese steel has a more homogeneous microstruc- 4ture with less banding and more uniform distribution of the carbides. The diameters of the fibres in the liner grades of steel wool approach microscopic dimensions and it may be Aconceived that a more homogeneous microstructure will produce a more uniform steel wool bre. That is, as the fibres are cut olf they are not seriously distorted and likewise not made fragile as might occur in steel of less favorable composition or structure. Hence the result is greater ease of 'machining and a softer wool with the improved physical characteristics described above. This COHCePtion of the desirable influence ofiimproved patented wire of the higher manganese content.

This patenting heat treatment hask been found very beneficial for steel wool wire. Y' Effective response of the steel to the patenting temperature gives a more homogeneous sabine-microstructure with the carbidesmoref uniformly distributed and with less ferritelbanding. In wire with the higher manganese content of this invention I find better response to Lpatenting. The benecial effect of the higher manganese content on the microstructure. machinability, and henceron the quality of the steel wool, particularly softness and resiliency, is evident also in unpatented wire, but the best results are obtained when the higher manganese steelvwire is patented. l

I have found thatmlybdenum and chromium additions to the steel up to4 about05 per cent, separately or together, have in general a similar improved effect to that of increased manganese content, and apparently for similar reasons. Molybdenum and chromium additions may be beneficially employed in conjunction with higher manganese. The manganese content may be held somewhat lower when addiitons of molybdenum or chromium or both are made, or as high a percentage of manganese may be used, as when molybdenum or chromium or both are not present.

The drawing shows a mass of steel wool, the showing being conventional so far as the wool structure is concerned. This drawing includes legends beneath the Wool representation indicative of the-field of compositions involved in the present invention.

The following are examples of compositions of Bessemer steel Wire heats which have given decidedly improved results in the manufacture of steel wool:

C Mn l P l S l Per cent Per cent Per cent Per cent l2 1. 10 08 034 .16 1.00 08 040 .12 .s4 .0s .03o .25% Mo 16 l. l5 08 040 l5 93 08 .050 .10% Cr 10 l. l0 07 028 f 1 .16 l. 26 07 055 .14 1.12 .08 .035 .10% Mo l0 1.25 .07 .030

l have found it desirable to favor relatively low phosphorus content, preferably below 0.09 per cent phosphorus. I also favor relatively low sulphur content preferably below 0.05 per cent sulphur.

E have also found it advisable to employ considerable cold Work by using greater percentages ci. reduction in drawing the wire from the rod than is conventional wire mill practice. This may be accomplished by drawing either on individual blocks or by continuous wire drawing equipment in which several dies are arranged in tandem. To obtain the best results careful technique in the wire mill must be employed; this contributes to the toughness of the wire and to the softness of final steel wool libres.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. Steel wool containing under about 0.35 per cent carbon and from about 0.95 to about 1.5 per cent manganese and the remainder being substantially all iron.

2. Bessemer steel wire for the manufacture of steel wool containing under about 0.35 per cent carbon and from about 0.95 to about 1.5 per cent manganese and the remainder being substantially all iron.

ascissa 3. Patented Bessemer steel wire for the manu= facture of steel wool containing under about 0.35 per cent carbon and from about 0.95 to about 1.5 per cent manganese and the remainder being substantially all iron.

4i. Steel wool containing carbon less then .35 per cent, and metal o the group consisting of manganese, molybdenum and chromium, in amount not less than .95 per cent and not greater than 2.5 per cent, the balance being substantially 5. Steel Wool containing carbon less than .35 per cent, manganese in substantial amount up to 1.5 per cent, and molybdenum in substantial amount up to .5 per cent, the combined amounts of manganese and molybdenum being not less than .95 per cent nor more than 2.00 per cent, and the balance substantially all iron.

6. Steel wool containing carbon less than .35 per cent, manganese in substantial amount up to 1.5 per cent, and chromium in substantial amount up to .5 per cent', the combined amounts of manganese and chromium being not less than .95 per cent nor more than 2.00 per cent, and the balance substantially all iron.

LOUIS H. WINTQLER.

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