D307 in line with GB / T 984 EDD-D-15 Description: D307 is a low hydrogen sodium type coating of welding electrodes, DC reverse. Uses: in the carbon steel (such as 45,45Mn steel) tool made of rough cut to achieve the alternative surfacing on the overall purpose of high-speed steel, tool wear can also be surfacing repair and other tools. Deposited metal chemical composition of the total of other elements (%) C Cr WVSP guaranteed 0.70 ~ 1.00 3.80 ~ 4.50 17.00 ~ 19.50 1.00 ~ 1.50 ≤0.035 ≤0.040 ≤1.50 cases 0.85 4.00 19.00 1.35 0.009 0.020 - Surfacing layer hardness: (540 ℃ after welding after tempering three times) HRC≥55 Reference Current (DC +) Electrode Diameter (mm) f3.2 f4.0 f5.0 welding current (A) 100 ~ 130 130 ~ 160 170 ~ 220 Note: 1 . Before welding electrodes shall be 300 ~ 350 ℃ baking 1h. 2. surfacing small welding preheat to 300 ℃, large parts preheated to 600 ℃. 3. The welding heat treatment conditions W18Cr4V high-speed steel tools with specifications.