1、 FORD LABORATORY TEST METHOD BQ 008-01 Date Action Revisions 2000 11 09 Revised Editorial no technical change A. Cockman 1992 08 05 Printed copies are uncontrolled Page 1 of 2 Copyright 2000, Ford Global Technologies, Inc. WELDING ACCEPTANCE TEST FOR PROTECTIVE COATINGS Application This procedure is
2、 used as a welding qualification test for materials such as zinc rich primers used as protective coatings on automobile bodies. Scope The procedure consists of two tests - A and B. Test A is for coatings which can be used only in the faying surfaces and are applied on flat sheet by the roller coated
3、 method. Test B is for coatings which are applied on either subassemblies or sheet steel by roller coat, brush, dip or spray appl ication. Equipment and Instrumentation Required Spot Welder A single point spot welder having a low inertia head shall be used. At a transformer tap setting of 4.0 - 5.0
4、volts, open circuit, secondary voltage, adjustments shall be made to obtain the fo llowing weld schedule: Electrode force - 550 lb Weld time - 12 cycles Secondary amperes - 12,500 At the above current level, the secondary current trace shall be a full sine wave, starting at the zero degree point on
5、the first half cycle. Electrodes Two WA 2510 spot welding electrodes, having a 1/4 inch diameter face and a 45 truncated cone. Instrumentation A galvanometer - type oscillograph shall be used for recording the sine wave of the secondary current. Test Coupons and Panels Test coupons shall be 1 x 3 x
6、036 inch CR LCOH quality, steel body stock. Test panels shall be 4 x 12 x .036 inch CR LCOH body stock. All coupons and panels shall be clean and free from burrs or ragged edges that might provide a shunt path for the welding current. Prepar ation of the coupons and panels shall be as described by
7、the applicable material standard. FORD LABORATORY TEST METHOD BQ 008-01 Page 2 of 2 Copyright 2000, Ford Global Te chnologies, Inc. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relat ive
8、humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure Test A 1. Prepare 50 test coupons, 1 x 3 x .036 inch, with the test coating applied on one side of each coupon. Refer to th e applicable material standard for type of applicati
9、on (spray, brush, etc.), coating thickness and bake cycle. 2. Prepare 25 assemblies by placing two coupons face to face on their coated sides and successively weld each assembly as specified. 3. Examine the secondary current trace of each weld for length of time in half cycles that is required to re
10、ach 90 % of full welding current. The primer under these conditions shall require two half cycles or less to reach 90 % of full welding current on all 25 wel ded coupons. Test B 1. Repeat Test A with the primer applied on both sides of each coupon. The primer shall require three half cycles or less
11、to reach 90 % of full welding current on all 25 welded coupons. 2. Prepare sufficient test panels, 4 x 12 x .0 36 inch, with the primer applied to both sides of each test panel so that 2,000 consecutive spot welds may be made. Test coupons, 1 x 3 x .036 inch, for checking the weld button at the begi
12、nning and end of the test should be prepared at the same time. 3. Place two 1 x 3 x .036 inch coupons together, coated in the same manner as the test panels, and make two spot welds 1 1/2 inch apart with a weld button .25 - .26 inch in diameter (to obtain this quality of weld, a 10 % deviation from
13、the above specified w eld schedule is permissible). 4. Place the 4 x 12 inch test panels together with the primer on both sides and make 2,000 consecutive welds at the rate of 15 spot welds per minute. The welds shall be made without attention to the electrodes or adjustment of the weld schedule. Af
14、ter the 2,000 welds, test coupons, 1 x 3 inch coated in the same manner as the panels, shall be welded and upon destruction, the weld button shall measure a minimum of .22 inch. Note: During the above tests, there shall be no co nstant or violent metal expulsion nor excessive smoke or fumes which ar
15、e irritating to the operator. Periodic metal expulsion which is characteristic of most coating materials is acceptable. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities.
