Patent GB-568397-A (GB)
Title: An improved method of and apparatus for flame-cutting or flame-desurfacing a metal body
IPC: B23K7/08
Filed: 1943-06-19
Abstract: 568,397. Dividing or removing surface metal by fusion. LINDE AIR PRODUCTS CO. June 19, 1943, No. 10203. Convention date, Aug. 29, 1942. [Class 83 (iv)] [Also in Group XI] In flame-cutting or flame de-surfacing a metal body having a composition which resists the removal of molten metal by the impingement of the oxygen jet thereof, finely divided oxidisable adjuvant material such as an oxidisable metal or alloy is carried by the oxygen jet into the zone of reaction between the jet and the heated portion of the work to lower the melting point of the thermo-chemical reaction products resulting from the action of the jet on the heated work so as to facilitate removal of such products by flowing away or being blown away by the oxygen jet. The body to be cut or de-surfaced may contain one or more constituents, the oxides of which have a higher melting point than that of the metal of the body. It may consist of cast-iron, high alloy steels such as stainless steel, copper, nickel, aluminium, and alloys such as nickel-molybdenum, nickel-molybdenum-chromium, cobalfchromium-tungsten and silicon bronze, and the finely-divided metal powder may consist of manganese, ferromanganese, tin, iron, tin-iron alloy, steel, lead and mixtures of manganese with cast-iron or steel, such powder for use with cast-iron, or with steel containing over 5 per cent of chromium, e.g. 25 per cent, cutlery steel containing 12-14 per cent of chromium and steel containing about 18 per cent of chromium and 8 per cent of nickel or manganese may consist of ferromanganese, manganese, iron, mild steel, tin-iron alloy or mixtures of manganese with steel or cast-iron, and for use with nickel, copper, aluminium, cobalt-chromium-tungsten alloy, copper-silicon alloy containing 95 per cent of copper, brass containing 50 per cent each of copper and zinc, alloys containing 20 per cent of molybdenum, 20 per cent of iron, 60 per cent of nickel, or 30 per cent of molybdenum, 5 per cent of iron, 65 per cent of nickel or 17 per cent of molybdenum, 8 per cent of iron, 60 per cent of nickel and 15 per cent of chromium may consist of low carbon ferromanganese, iron, tin, or lead, copper plate to be cut is preheated to about 900‹ C. and aluminium is preheated to 400‹ C. The powder may be drawn into the oxygen stream by suction produced either in the nozzle or at the end thereof, the nozzle N of the blowpipe comprises front and rear parts F, R screwed together and provided with gaskets 25, 29. The rear part, which contains the preheating gas passages 22 and the central oxygen passage 12 is bevelled at 23 and secured by a nut 24 in the head 18, and has an annular channel 27 connecting with the gas passages 28, 11 in the front part, which has a chamber 16 containing a nozzle 14 with constricted bore 13. The nozzle 14 has a bevelled end 15 and is screwed into the part R. The powder is conveyed from a pile 32 through a pipe 31 and passage 17 into the chamber 16, the oxygen flowing through the bore 13 at sufficient velocity to produce a suction effect in the chamber 16 to draw the powder through the passage 17. The pile 32 is contained in a pan 33 fed from hopper 34 with valve control 35, the pan being kept filled so that the powder is of shallow but constant depth, any powder falling over the sides being caught in an overflow pan 36. The supply of powder is regulated by air or gas introduced into the tube 31 through a valved tube 37. The valve 38 is normally only opened when the suction effect of the oxygen is too great. In another form, Fig. 6, a standard cutting nozzle with central oxygen passage and surrounding preheating passages has welded or brazed thereto a blank 42 to which the powder supply tubes 44 is attached, the exit 43 from the block being close to the mouth of the oxygen passage so that a suction effect across the mouth of the exit 43 is produced to draw the powder into the oxygen jet. The powder may be supplied to the oxygen jet by gravity.