US1432923A - Acid-proof casting - Google Patents

Description

Patented Oct. 24, 1922.

UNITED STATES PATIENT @FFHCZE.

HENRI TERRISSE AND MARCEL LEVY, OF GENEVA, SWITZLALND.

ACID-PROOF CASTING.

Ho Drawing.

ing iron and silicon may be obtained, and- I that such castings will be proof against mineral acids especially halogen acids, when said castings contain about to 30 per cent of silicon. Such castings, however, cannot be easily made on account of the brittle nature of the mineral which will easily disintegrate and crumble to pieces. It is also known that ferro-tungsten and ferro-vanadium castings will also become acid-proof if a high percentage of tungsten or vanadium is used, but these alloys do not give very satisfactory acid-proofness; and furthermore all such alloys of tungsten, vanadium or a mixture thereof are very difiicult to cast.

We have found that all these disadvantages can be overcome, and that easily moulded castings which will have a very high resistance, either when cold or when warm, against halogen acids and other min-.

eral or organic acids can be obtained. To

these ends, in accordance with the present invention, we make castings from mixtures of iron, silicon and a metal adapted to increase the mechanical, and chemical resistance of the casting, such as, for example, tungsten,

9 or, vanadium, or a mixture of. the four metals.

In forming such castings, we subject ferro-silicon to heat to melt the same; and while in the molten state, we add thereto at least one metal to increase its mechanical and chemical resistance, such metal being,

for example, tungsten or vanadium.

These metals may be added either in a combined form, such as ferro-tungsten or ferro-vanadium, or as the silicide of tungsten or silicide of vanadium. I

In carrying out the process, iron and sili- Application filed July 8,-1920. Serial No. 394,722.

the molten metal and a homogeneous, easily con are chosen so as to form' ferro-silicon with from 10 to 30 per cent of silicon, so as to obtain an alloy having a melting point at about 1200 to 1300 C. 'A metal such as ferro-tungsten or ferro-vanadium is then added thereto, so as to obtain an alloy containing from 2 to 20 per cent and more oftungsten or vanadium.

The castings thus produced will have great brightness and will not tarnish when exposed to the air and they will also have great acid-proofness and can be easily.

moulded. In analyzing such alloys, it has been found that there will exist most probably some ternary combinations of iron, silicon and tungsten or of iron, silicon and vanadium, which combinations are very stable.

The ingredients may be used in about the following proportions:

186 E mampla-lOO kilograms of ferro-silicon having 20 per cent silicon are melted down, and 30 kilograms of ferro-tungsten havin 50 per cent tungsten are added thereto. he tungsten is rapidly dissolved in running mass will be obtained. If a rapid chilling is desired, the casting is completed by usin chills.

2nd acample.l00 kilograms of ferrosilicon having 15 per cent silicon are melted down, and 28 kilograms of tungsten silicide having 19 per cent silicon are added thereto; the subsequent procedure being the same as in the first example. Ferro-vanadium and silicide ofvanadium may be used instead of ferro-tungsten and silicide of tungsten.

We claim: I An acid proof casting which has great mechanical and chemical resistance made from an alloy containing iron, silicon, and tungsten, and which contains from ten to thirty per cent silicon and from two to twenty per cent of tungsten.

In testimony whereof we afiix our signatures in presence of two witnesses.

' HENRI TERRISSE.

MARCEL LEVY. Witnesses: Dr. Ron. DE WURTEMBERG,

THEODORE I