Standard Specification for Hot Tin and Hot Tin/Lead Dip on Ferrous and Non-Ferrous Metals

1.1 This specification covers tin and tin/lead coatings applied by the hot dip process on ferrous and non-ferrous metals. hot tin and tin/lead coatings are used to provide a low contact-resistance surface, to protect against corrosion, to facilitate soldering, to provide anti-galling properties, and to be a stop-off coating in the nitriding of high-strength steels.

1.2 This specification is intended to be applicable to items that are reflowed, centrifuged or otherwise handled to remove excess tin or tin/lead bath metal. Coating thickness grade requirements reflect this.

1.3 Some corrosion can be expected from tin or tin/lead coatings exposed outdoors. In normal indoor exposure, tin or tin/lead 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 the tin or the tin/lead and the underlying metal through the discontinuities, especially in humid atmospheres.

1.4 This specification applies to hot tin dip coatings of not less than 99.8 % tin and to hot tin/lead dip coatings of 60 ± 5 % tin and the balance lead.

1.5 This specification does not apply to electrodeposited coatings of tin or tin/lead.

1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.