1. Electrode Recommendation:
In accordance tensile stretch level, engineering design and workpieces type, choice different welding method and consumables. Ex. Classification by 70Ksi or 80Ksi tensile strength suggest for construction industry. But welding method would use SMAW, FCAW, GMAW, SAW, EGW and ESW option.
Electrode identification by a steel rod
covered flux means covered electrode. AWS and JIS classification for Carbon
Steel Electrodes a following:
|
Type of Covering
Specification |
Classification |
High titania sodium
|
Iron oxide titanina potassium |
High titania potasium |
High Cellulose type |
Low-hydrogen |
Low-hydrogen iron powder
|
Iron powder, titaniar |
Special type |
||
|
AWS A5.1 |
-- |
E6019 |
E6013 |
E6010
E6011 |
E7016
E7048 |
E7018 |
E7024 |
-- |
|||
|
JIS Z3211 |
E4303 |
E4319 |
E4313 |
E4310
E4311 |
E4916
E4948 |
E4918 |
E4924 |
E4340 |
|||
|
Weld result
|
Anti-crack |
○ |
○ |
△ |
○ |
Ⓞ |
Ⓞ |
△ |
○ |
||
|
Porosity defect |
○ |
○ |
△ |
△ |
Ⓞ |
Ⓞ |
△ |
○ |
|||
|
Impact result |
○ |
○ |
△ |
△ |
Ⓞ |
Ⓞ |
△ |
○ |
|||
|
Management |
Welding position |
Flat |
Ⓞ |
Ⓞ |
Ⓞ |
△ |
○ |
○ |
Ⓞ |
Ⓞ |
|
|
Horizontal fillet |
Ⓞ |
Ⓞ |
Ⓞ |
△ |
○ |
○ |
Ⓞ |
Ⓞ |
|||
|
Vertical-up |
Ⓞ |
Ⓞ |
Ⓞ |
○ |
Ⓞ |
Ⓞ |
－ |
Ⓞ |
|||
|
Vertical-down |
△ |
－ |
△ |
Ⓞ |
Ⓞ*1 |
Ⓞ |
－ |
△ |
|||
|
Overhead |
Ⓞ |
Ⓞ |
Ⓞ |
○ |
Ⓞ |
Ⓞ |
－ |
Ⓞ |
|||
|
Groove weld outlook |
Flat |
Ⓞ |
○ |
Ⓞ |
△ |
△ |
△ |
Ⓞ |
Ⓞ |
||
|
Horizontal fillet |
Ⓞ |
○ |
Ⓞ |
△ |
△ |
△ |
Ⓞ |
Ⓞ |
|||
|
Vertical /Overhead |
Ⓞ |
○ |
Ⓞ |
○ |
Ⓞ |
Ⓞ |
－ |
Ⓞ |
|||
|
Penetrate |
○ |
Ⓞ |
△ |
Ⓞ |
○ |
○ |
△ |
○ |
|||
|
Spatter |
○ |
○ |
Ⓞ |
△ |
○ |
○ |
Ⓞ |
○ |
|||
|
Slag removable |
Ⓞ |
○ |
Ⓞ |
Ⓞ |
△ |
△ |
Ⓞ |
Ⓞ |
|||
|
continuous arc welding |
Ⓞ |
－ |
Ⓞ |
Ⓞ |
－ |
－ |
Ⓞ |
Ⓞ |
|||
Note:
Ⓞ: Very well ○: Well △: Bad －: Not availble
※1: Special for vertical down welding position (AWS A5.1 E7048)
2.Tips for welding:
1. Storage & handing:
①Storage must be dry to perform properly. In order to avoid moisture absorb, DO NOT storing with excessive moisture (≧80%R.H) and higher temperature (≧30℃) ambient.
②Non-low hydrogen type proper absorb moisture easily than Low Hydrogen electrode. Due to that, restores the electrodes is more important.
③Low hydrogen electrodes to be re-dried should be removed from the can and spread out in the oven because each electrode must reach the drying temperature. Store electrodes from the open containers in heat cabinet at 100~150℃. Remove few electrodes from the container to avoid long exposure high humidity. Please follow up re-drying indication as attachment.
2.Caution:
②In order to avoid porosity or crack defect by moisturize, please ensure short arc welding for low hydrogen electrode.
③Based on low hydrogen electrode welding, the relative position of the weld bead and flame/arc keeping 1~2cm, welding technique can be of two types – forehand and back hand. Use forehand welding to push welding arc eliminate porosity defect.
④In order to maintain weld metal quality, the
weaving volume is usually limited to 3 times the electrode core diameter.
⑤Windproof measures requirement, when wind flow over than 3m/s from out door. Air entrainment nitrogen in welding bead. Porosity and low impact resistant might be caused by the absorption of nitrogen.
⑥WPS does not allow excess heat input, that would be caused bigger grain and low impact resistance.
