AWS G2.4/G2.4M:2014 pdf free download

AWS G2.4/G2.4M:2014 pdf free download.Guide for the Fusion Welding of Titanium and Titanium Alloys.
moisture in the shielding gas. The purity of the shielding gases should be at least 99.995% but it is recommended that higher purity gas be used. The dew point of the gases should he —58°F [—50°C] or lower. Shielding gases conforming to requirements of AWS A5.32/A5.32M (ISO 14175 MOD), Welding Consumables—Gases and Gas Mixwresjr Fusion and Allied Processes, are recommended for titanium. The purity and dew point requirements from this specification are provided in Table 4.
8.4 Inert Gas Distribution. Shielding gases are supplied in pressurized cylinders or as a liquid in both portable dewers and large stationary insulated tanks. For central liquid systems, the liquid is vaporized and the gas is piped to points within the fabrication facility through a distribution system. Gas distribution lines should be welded stainless steel or brazed copper tubing, except where flexibility or electrical insulation are required. All manifolds, valves, regulators, flow- meters. fittings, tubing, hoses, torches, and other associated equipment should be clean, leak-free, and free of moisture.
If pressurized cylinders are used, it is inevitable that they will contain a small amount of moisture. This level is extremely low when the gas cylinder is full, but as the pressure in the cylinder drops, the moisture content as a percentage of the shielding gas, increases. Some titanium fabricators use the cylinder until the pressure has fallen below 1000 psi [6895 kPa]. at which time it is used to supply gas for welding less sensitive metals. Inert gas for the torch, trailing, and backup shielding should be supplied through separate flowmeters. Interlocked timed solenoid valves or manual on-off valves are used to control pre-flow and post-flow of gas. A suggested arrangement is a timer-controlled pre-flow and post-flow for torch shielding and solenoid valves with manual switches interlocked with the welding current for trailing and backup shielding. It is also a common practice (although wasteful) to use bottle or manifold shutoff valves for trailing and backup shielding, continuing to allow the gas to flow throughout the welding session.
Gas hoses should he nonporous, flexible, and made only of polytetrafluoroethyene (PTFE), polypropylene (PP), or high density polyethylene (HDPE). Fluorinated ethylene propylene (FEP)-lined Tygon® has superior resistance to moisture absorption and is recommended. Air and moisture permeates through rubber hose which should never he used in any titanium welding operation. Periodic inspection of the gas delivery system for fitting, leaks, hose cracks, and pinholes is recommended. Joints and hoses can he checked for leaks using a weak solution of a detergent in water or a leak-detecting solution from a gas supply company. Gas hoses should he kept off the floor as much as possible to keep them clean and prevent damage.AWS G2.4/G2.4M:2014 pdf free download.