In the previous post you have learnt the significance of primary or initial shielding of titanium welding wire and now we'll discuss in detail about the secondary and backup shielding that also have equal significance like initial shielding.
Basically the secondary shielding is endowed by straggling shields. The purpose of the straggling shield is to defend the solidified titanium weld metal and connective heat influenced zones up to the temperature of 800°F (427°C) or lesser. The straggling shield is basically custom made to fit in the torch and specific welding application. The layout of the straggling shield is compact that allows the consistent flow of inert gas inside the equipment. The viable requirement of water cooling is considered on the base of certain huge protection requirements. The spongy bronze diffusers are endowed and nonturbulent supply of inert gas from the shield directed to the weld.
On the other side the backup shielding aims at supplying the inert gas shielding to the source side of the welds and their heat influenced areas. The equipments generally seem like the straggling shields and can be hand held or fasten into a place. The water frozen copper backup bars can be purposed as heating sinks to the cool the welds. The frozen bars are channeled with the groove present exactly beneath the welding point. In the region of about 10 cfh the inert gas flows per linear foot of channel is essential to obtain desired shielding.
The temporary shielding equipments are generally engaged with the titanium welding wire under the certain conditions that include the plastic usage to cover the entire weld and feed it with the inert gas just like aluminum or stainless steel foil are downpoured with the inert gaseous are utilized in the form of backup shields. While implementing such methods, it becomes essential to remove the contaminated air from the process. The inert gas cleanse for ten times the volume of air eradicated is better thumb law for uneven regions. A fine speed of inert gas should be preserved to complete the welding process.
Argon is preferably chosen as compare to helium to utilize in the irregular shields and backup equipments preferably those with economical and denser characteristics.The welded joints of titanium welding wire are similar to other metallic joints. The joint layout of titanium allows the inert gas protection of both root and face while in the welding and post welding for both sides of metal. The connected surface should be plant, dirt less and totally isolated from the contagion. The flam signs produced in the grinding or mechanical filing must be eradicated by casing. Similarly the pointed edges must also be eradicated using sharp file and on other using sandpaper or steel wool may cause the introduction of contaminated particles in the welding region.
The titanium welding wire needs the better joint fitting since the consistent fitting ensures the lesser burns and restricts the under bead contour. On the other side the fault fittings may increase the chance of contagion due to air restoration in the joining points.