GB1319465A - Tubular arc-welding electrode - Google Patents

Abstract

1319465 Welding by fusion BRITISH OXYGEN CO Ltd 16 Sept 1970 44229/70 Heading B3R A tubular welding electrode including chromium and iron, for depositing, without external flux or gas shielding, high chromium, high carbon, hard facing metal, comprises a metallic sheath enclosing core material including boron (a) a boron-containing alloy powder (for fluxing and weld edge wetting) and (b) free carbon (for arc stabilizing), chromium being included in the sheath and/or core material. The boron may be retained in the deposit. The boron may be in the form of chromium-aluminium boron, ferro-boron, ferro-aluminium-boron, mangansee - aluminium boron or other boroncontaining powders, or as mixtures thereof. The free carbon may be in the form of graphite or carbon black. The chromium may be present in the core as chromium, ferro-chromium, carbon-chrome or other high chromium alloy powders, or as mixtures thereof. Satisfactory quantity ranges of the essential ingredients, in per cent total electrode weight are chromium .. .. 10-60 boron .. .. .. 0À2-5À0 free carbon .. .. 0À2-5À0 In the following mild steel sheath examples, the core is 30% total electrode weight and comprises in per cent core weight Example 1: carbon-chrome .. .. 86 chromium-aluminium-boron 10 graphite .. .. .. 4 the chromium, boron and graphite being respectively 25À5, 0À45 and 1À2% total electrode weight. Example 2: ferro-chromium .. .. 78 ferro-boron .. .. .. 20 graphite .. .. .. 2 the chromium, boron and graphite being respectively 16À4, 1À2 and 0À6% total electrode weight. In the following example the sheath is of stainless steel comprising 17% wt. chromium, and the core is 40% total electrode weight and comprises in per cent core weight Example 3: carbon-chrome .. .. 80 chromium-aluminium-boron 15 graphite .. .. .. 5 the chromium, boron and graphite being respectively 43À6, 0À9 and 2% total electrode weight. The sheath or core may include one or more of the following supplementary metals (as elements or alloys): molybdenum, niobium, titanium, tungsten, vanadium and zirconium (to form or modify carbides or borides) and manganese and nickel (to produce an austenitic matrix embedding the carbides and borides). The following examples are of cores which include carbide-forming supplementary metals and comprise in per cent core weight Example 4: carbon-chrome .. .. 76 ferro-boron .. .. .. 15 ferro-molybdenum.. .. 5 graphite .. .. .. 4 Example 5: ferro-chromium .. .. 78 chromium-aluminium-boron 12 tungsten metal powder .. 5 graphite .. .. .. 5 Example 6: ferro-chromium .. .. 75 ferro-boron .. .. .. 15 ferro-vanadium .. .. 6 graphite .. .. .. 4 Example 7: carbon-chrome .. .. 73 ferro-boron .. .. .. 15 ferro-molybdenum .. .. 4 ferro-vanadium .. .. 4 graphite .. .. .. 4 Electrodes containing carbide-forming supplementary metals may have a mild, low alloy or chromium-bearing high alloy steel sheath which may contain some or all of said supplementary metals. In the following mild steel sheath examples, the cores are 35% total electrode weight, include austenite-forming supplementary metals and comprise in per cent core weight Example 8: carbon-chrome .. .. 75 ferro-boron .. .. .. 10 ferro-manganese .. .. 10 graphite .. .. .. 5 Example 9: carbon-chrome .. .. 75 ferro-boron .. .. .. 10 nickel powder .. .. 10 graphite .. .. .. 5 In the following example wherein austenitic forming metal is derived from the sheath, the latter is of stainless steel comprising 18% chromium, 8% nickel, and the core is 30% total electrode weight and comprises in per cent core weight Example 10: ferro-chromium, .. .. 80 ferro-boron .. .. .. 15 graphite .. .. .. 5 the chromium, nickel, boron and graphite being respectively 29À4, 5À6, 0À9 and 1À5% total electrode weight. In the following example wherein austeniteforming nickel and manganese are respectively derived from the sheath and core, the sheath is of stainless steel comprising 18% chromium, 8% nickel, and the core is 35% total electrode weight and comprises in per cent core weight ferro-chromium .. .. 75 ferro-boron .. .. .. 10 ferro-manganese .. .. 10 graphite .. .. .. 5 the chromium, nickel, manganese, boron and graphite being respectively 30, 5À2, 2À7, 0À7 and 1À75% total electrode weight. The carbide-forming and austenite-forming supplementary metals are not to exceed respectively 10 and 20% total electrode weight. The electrodes of the invention may be used for A.C. or D.C. welding.