抄録
In order to develop a shop primer for giving the highest weldability and gas-cutting ability of steels, experiments were conducted on the steel coated with various kinds of shop primers.
The employed shop primers included 70 kinds. Their groups and kinds were as follows:
20 kinds……prepared by the combinations of various resins and pigments
22 kinds……prepared by the combinations of phenoxy resins and various pigments
6 kinds……prepared by various PVC (volume concentration of pigment) value
4 kinds……prepared by various compositions of solvents
6 kinds……for various coating thicknesses
12 kinds……for several commercial shop primers
The coating thickness of primers was about 25μ, except for the above 6 kinds which were in the range of 10-40μ.
Blank tests were conducted for reference on the uncoate3 steel.
Arc welding was carried out by manual and butt weld.
Welding usability test and bead appearance test, X-ray inspection, tension test, roller bending test of the weld zone, and gas cutting ability test were carried out on these test pieces.
The results obtained were as follows:
1) Phenoxy resins showed considerably superior weldability of steel; but chlorinated rubber resins, acrylic resins, and pigment of lead type were inferior. Generally speaking, the effects of shop primers on weldability of steel seemed to be somewhat different according to the combinations between resins and pigments.
2) Non zinc shop primers, D and E, showed the highest weldability and cutting ability among 70 kinds of the primers.
3) The commercial shop primers showed superior weldability to trial primers.
4) Chlorinated rubber resins showed the lowest gas cutting ability. Phenoxy, alkyd, and ketone resins showed fairly high cutting ability.
5) The commercial shop primers, except for those of zinc rich type, showed fairly high gascutting ability.
6) The effects of coating thickness of weld on welding and gas-cutting were not observed in such a narrow range of 10-40μ.
