METHOD OF WELDING MATERIAL ONTO RAILS

摘要

Described is an automatic or semi-automatic method of welding additional material onto the worn top and/or side surfaces of steel rails using a flux at pH 1.3 to 3.2, the rails having the following chemical composition by weight: carbon 0.45 to 0.82 %, manganese 0.7 to 1.5 % and silicon 0.07 to 0.55 %, the remainder being iron and manufacturing impurities. The additional material has the following chemical composition by weight: carbon 0.06 to 0.10 %, manganese 0.5 to 1.5 % and silicon 0.05 to 0.5 %, the remainder being iron and manufacturing impurities. It is applied to the head of the rail with an arc giving a heat input Q of (5.9 to 8.0 kJ/cm) x K at a speed of advance v of 40 to 75 cm/min, where Q = eta x 60 x U x I/v, eta being the efficiency, U the voltage, I the current and v the speed of advance and K being 1 for welding material on to the top of the rail and K being 2.6 for welding material on to the sides. If the material is alloyed with up to 5 % by wt. in total of the following alloys: nickel 1.8 to 4.5 %, vanadium 0.0 to 0.2 %, molybdenum 0.0 to 0.3 %, niobium 0.0 to 0.1 %, chromium 0.0 to 0.4 %, aluminium 0.0 to 1.6 % and titanium 0.0 to 0.1 %, the upper heat-input limit is increased to 11.5 kJ/cm.