Welding positional

Step 3 Decide combined thickness of joint in question (Chapter 3). Step 4 Decide limitations on heat input, bead size, or electrode size which can he used (Chapter 3). These limitations may arise because of positional welding or because of a need to achieve minimum toughness levels in weld metal or HAZ. Step 5 Trace horizontal line to obtain required preheat level. 

Hart P H M The influence of steel cleanliness on HAZ hydrogen cracking the present position . Welding in the World/Soudage dans le Monde 23 (9-10) 1985 230-239. Also Doc IIW/IIS828-85 (ex Doc IX-1308-84). 

Welds made in vertical position weld reinforcement removed, t (Minimum stress)/(maximum stress) = 0. 

For AC and DC electrode-positive welding, the desirable electrode tip shape is a hemisphere of the same diameter as the electrode. This tip shape on the larger electrodes required for AC and DC electrode-positive welding provides a stable surface within the operating current range. Zirconia-type... 

Slags from rutile (titania-based) coatings are easily detached and have a good bead shape. In contrast, slags from basic-coated electrodes for out-of-position welding can be difficult to remove small particles of slag may remain on the surface, providing an easy initiation site for crevice attack. 

Portable semi-automatic (manually operated) or fully automated d.c. systems and robot mounted. Three types of metal transfer to the weld area dip and pulsed transfer use low current for positional welding (vertical, overhead) and thin sheet spray transfer uses high currents for thick sheet and high deposition rates, typically for horizontal welding. 

Slag created when using a flux-cored wire may aid the control of the weld profile and commonly used for site work (windy conditions where the shielding gas may be gusted or positional welding) and large fillet welds. 

The protective slag can help the weld to keep its shape during positional welding. 

The rapid solidification of the weld metal allows truly all positional welding... 

Position the 2 length of black pipe on the cross brace as shown in figure 67. Align the inside diameter of the pipe with the hole in the cross brace. When in position, weld the pipe to the cross brace. 

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