AWS D3.9-D3.9M:2019 pdf download.Specification for the Classification of Weld-Through Paint Primers
1.1 Scope. This standard specifies the requirements for classification of weld-through paint primers only. The paint primers are classified based on the maximum coating thickness for successful welding and the welding procedure used during the classification test. This standard provides a system for paint manufacturers to classify the weldability features of weld-through paint primers. This standard is limited to weld-through paint primers only and does not include galvanized or other types of protective coatings.
1.2 Units of Measurement. This standard makes use of both the U.S Customary Units and International System of Units (SI). The latter are shown within brackets [] or in appropriate columns in tables and figures. The measurements may not be exact equivalents; therefore, each system must be used independently.
1.3 Safety. Safety and health issues and concerns are beyond the scope of this standard; some safety and health information is provided. but such issues are not fully addressed herein.
Work performed in accordance with this standard may involve the use of materials that have been deemed hazardous, and may involve operations or equipment that may cause injury or death. This standard does not purport to address all safety and health risks that may be encountered. The user of this standard should establish an appropriate safety program to address such risks as well as to meet applicable regulatory requirements. ANSI Z49.1 should be considered when devel-pping the safety program.
4.1 Base Material. The base material shall be ASTM A36/A36M, ASTM A131/A131M or other steel with a minimum specified yield strength that does not exceed 50 ksi [350 MPa].
4.2 Surfaces. All surfaces shall be blast cleaned in accordance with SSPC-SP 10/NACE No.2, Near-White Blast Cleaning with a surface profile of 1.5 to 2.5 mils [38 to 64 microns]. The surface profile shall be measured using a profile comparator (ASTM D4417, Method A), a profile depth gage (ASTM D4417, Method B) or replica tape (ASTM D4417, Method C).
4.3 Spray Paint. Following preparation, and attachment of shims (see 4.5), all surfaces shall be spray painted as uniformly as possible with the primer to obtain the required dry film thickness. In order to simulate welding of sections which have the bottom edge of the vertical piece primed, some tests may be carried out with the primer applied at double the required dry film thickness on side C, as shown in Figure 1. Where all tests qualifying a particular primer were performed on assemblies with double the required film thickness on side C, the suffix “2T" may be added to the classifications listed in section 6.2.AWS D3.9-D3.9M pdf download.