Parts are rack or barrel plated to ASTM B standard thicknesses from ” to “, depending on the base metal and application. Pure % tin is. Designation: B – 97 (Reapproved )e1 Standard Speci?cation for Electrodeposited Coatings of Tin1 This standard is issued under the. ASTM B Standard Specification for Electrodeposited Coatings of Tin.
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Calculate the coated area in mm2 to an accuracy of at least 1 part in There needs to be sufficient free tin below the oxide layer in order for this to occur, because the intermetallic compounds formed from tin and the basis metal will not react in this way 7.
For some applications, this requirement may be relaxed to allow for a small number of such defects per unit areaespecially if they are outside of or on the periphery of signi?
A bright coating completely covering the signi? Coatings subject to mild etchants are included.
Test Method B contains several plans and also provides instructions for calculating plans to meet special needs. Class A Minimum Thickness 2. Referenced Adtm purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Mild service conditions with less severe requirements than Class C below. Practically all of the following methods take into account the chief cause of b54 whiskering, which is the presence of stresses in the tin coating 8: These should be taken into account when designing for special applications. Rejection and Rehearing 9. Black spots or lines are evidence of mechanical damage or gross defects.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every? Drying can reverse the reaction. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. Rejection shall be reported to the seller promptly and in writing.
The thickness of such an undercoating is usually greater than 0. Thicknesses of 30 to ?
Evidence of diffusion is the formation of a layer of copper-tin intermetallic at the asym and diffusion of zinc to the surface if the substrate is brass. A thicker coating of nickel may be required in some situations for additional retardation. In normal indoor exposure, tin is protective on iron, steel, nickel, copper, and their alloys.
Corrosion can be expected at discontinuities in the coating such as pores due to galvanic couples formed between ast tin and the underlying metal through the discontinuities, especially in humid atmospheres.
MIL-T-10727 vs. ASTM B545
When Test Method B is used to measure these types of coatings, the measuring instrument shall be calibrated with thickness standards that have the same substrate and same composition of coating as the product. Parts coated with tin can be assembled safely in contact with iron and steel, tin-coated aluminum, yellow chromated zinc, cadmium, and solder coatings. Poor adhesion will be shown by the appearance of a loose blister that grows as rubbing is continued.
If they do not, Test Method B identi?
The clamp is attached to a load cell and to a transducer, which transmits a signal to a converter that adjusts the signal to a useful mode analog or digital for the recording instrument, computer, or strip-chart recorder. Originally approved in Your comments will receive careful consideration at a meeting of asm responsible technical committee, which you may attend. Similar to Class A, but for shorter-term contact applications and short shelf-life requirements, subject to purchaser approval.
If the pores are few in number, or away from signi?
ASTM B | General Metal Finishing
Some examples are given in Appendix X6. The test must yield a numerical value, and certain statistical requirements must be met. Three test methods are described in Appendix X3, while a simple dip test is given in Test Method B An underplating of nickel or copper must be used as a diffusion barrier on brass.