D687
Description:
D687 is low hydrogen sodium type coating of high chromium cast iron welding electrode, the use of DC reverse, the arc more stable, less spatter, less slag, easy slag, surfacing layer even with alloy cutting tools are difficult to carry out cutting, only Grind. Metallography is martensite and coarse composite carbides.
use:
For applications requiring strong resistance to abrasion, such as cone bit small shaft, coal hole excavator, lifting bucket, crusher roll, pump frame tube, mixer blade and so on.
Deposited metal chemical composition (%)
| C | Mn | Si | Cr | B | Other elements of the total |
guarantee value | 3.00 ~ 4.00 | 1.50 ~ 3.50 | ≤3.00 | 22.00 ~ 32.00 | 0.50 ~ 2.50 | ≤6.00 |
Example value | 3.75 | 2.30 | 2.35 | 29.00 | 1.20 | - |
Surfacing hardness: (air-cooled after welding) HRC ≥58
Reference current (DC + )
Electrode diameter (mm) | φ3.2 | φ4.0 | φ5.0 |
Welding current (A) | 90 ~ 110 | 140 ~ 160 | 180 ~ 220 |
Precautions:
1. Before welding electrodes to be 300 ~ 350 ℃ baking 1h.
2. Weldment must be preheated 400 ~ 600 ℃, and the workpiece rust, oil, etc. to clean and then surfacing.
3. The length of each surfacing to no more than 50 ~ 70mm is appropriate.
4. After welding the workpiece should be tempered at 600 ~ 700 ℃ 1h and then slow cooling, or the workpiece immediately into the dry and preheated sandbox or grass asylum slow cooling.
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