What Characteristics of LB-52NS Do the Users Count On?

The most important quality of the electrodes used in low-temperature applications is weld notch toughness sufficient enough to prevent brittle fractures in the component materials under severe service conditions. Notch toughness, however, is commonly affected by such variables in welding as heat input, plate thickness, cooling speed, welding position, and postweld heat treatment.

LB-52NS ensures adequate notch toughness over a wide range of these variables. In addition, specific technical data such as Crack Tip Opening Displacement (CTOD) and Sulfide Stress Corrosion Cracking (SSCC) are available, which are sometimes required for special applications. Such dependable performance and technical data helps users control the welding quality.

LB-52NS Accommodates Higher Heat Input

Heat input is electric energy applied to a weld, which is determined by welding current, arc voltage, and carriage speed. Higher heat input commonly causes coarse microstructure, thereby decreasing notch toughness. LB-52NS, however, can maintain fine microstructure with higher heat input compared with conventional electrodes, due to the specific chemical composition (Si-Mn-0.5Ni-Ti-B). Fig. 1 shows the notch toughness of LB-52NS weld metals as a function of heat input. The lowest line of the absorbed energies at minus 45*C in the figure suggests that heat input can be up to 45kJ/cm to ensure adequate notch toughness. As to

those at minus 60*C, the maximum heat input can be 35kJ/cm to ensure adequate notch toughness. In addition, this figure shows that notch toughness of LB- 52NS weld metal is not deteriorated by SR.

Fig. 1 - Charpy impact absorbed energy of LB-52NS weld metals as a function of heat input in welding thick-section butt joints

LB-52NS Ensures Adequate Notch Toughness Even in Thinner Plates

Fig. 2 - Charpy impact test results of LB-52NS (4mm (f)) weld metals in vertical-up AC welding (interpass temperature: 100-150'C).