Sixth - Adding a requirement for a consistent mirror finish is a cosmetic issue not a safety issue.

As a material issue, the finish of a material is related to fatigue (a mechanical property) and corrosion (a chemical property).

Mechanical Properties

toughness: involves ductility and strength and is a measure of the ability of a material to absorb energy. In more practical terms, toughness pertains to resistance of a material to fracture when stress concentrates - as it inevitable does - at a notch, a crack, perhaps a brittle constituent at a grain boundary. (1999:68)

When a metal is subjected to repeated or cyclic stresses that include a tensile component, it fractures by fatigue... reciprocating shafts, springs, or gear teeth ... a vessel that is pressurized and depressurized, or a seemingly static unit that endures sympathetic vibrations.(1999:78)

A fatigue crack is usually initiated at a metal surface and slowly moves in a direction perpendicular to the axis of the tensile load.... Eventually the cross-sectional area bearing the load becomes so decreased that it cannot withstand the tensile load. It breaks ... Because the initiation of fatigue is almost always at a surface, the avoidance of surface imperfections, sharp changes of contour, corrosion pits, and metallic inclusions is vital. The effect of surface finish on fatigue life is especially important, and test samples whose finish varies from rough turned to a high polish can show up an order of magnitude in the number of loading cycles to failure. (1999:79)

Based on this information about fatigue and the universal self-evident truth that body jewelry is never subjected to stresses that include a tensile component any argument based on this line of reasoning is faulty.  The mechanical properties of surface corrosion relate to implants not body piercing jewelry.

 

The balance of this discussion focuses on the need to exclude implants from teh field of body piercing for a mirror finish is a requirement of implants, not body piercing jewelry.

First of all, the environment is completely different. Body piercing jewelry exists outside the body separated either by skin or fibrous tissue without interacting directly with the the vascular system.

 For implants,

The most common cause of failure is fatigue, especially corrosion fatigue taht is initiated through crevice corrosion which arises at interfaces, for example, between the mating surfaces of a screw and a plate. An opportunity for body fluids to seep in here initiates pitting corrosion from which a crack can develop.

...wet or moist and contaminated. ... unprotected plain-carbon steels corrode, as do the low-alloy steels: but the stainless steels generally do not because their chromium content causes the formation of that important, protective, passive layer. They do not discolor in a normal atmospheric environment, nor are they attacked by dilute nitric acid... They were said, therefore, not to stain and so became known as stainless steels. (Introduction, 1999:1)

 

One of the errors APP and others make is failing to acknowledge that the environment for body piercing jewelry is not the same as for orthopedic implants. The specific properties of a stainless steel alloy to survive in a bio-active, mechanically and physically stressed environment is far different than the properties required for a belly ring that is outside and separate from the body in an air-exposed dry atmosphere. That makes all the difference in the world.

It is the same with 316LVM, a patented product with a reduced ferrite content and decrease in impurities important for orthopedic implants, such as joint implants, and applications under stress and mechanical wearing. In a load-bearing joint implant two mating surfaces rub against each other with up to 150% of body weight, cyclically loading and unloading. This rubbing under pressure, starting and stopping, causes atoms to separate from the implant surface and become free-floating, as it were, between the two surfaces which increases ultimately resulting in the loss of the implant to the patient. Currently this is seen as inevitable. A s/s implant is found to last longer when a more homogenous, purer form of material is used freer from impurities, and what are called ferrites.


The developments relate not only to chemical composition ... [but] Heat treatments, fabrication techniques, the steelmaking process...some retain their toughness [at] .. very low temperatures only slightly above absolute zero. All have specific features of resistance to corrosion, although ... none is universally applicable. (Introduction 1999:2)

There are about two hundred commercially available stainless steel compositions, each with properties that are influenced by heat treatment and the manner of fabrication .. [there are many factors] that should influence our selection {when specifying the qualities necessary for a particular application or use.]. (Intro 1999,7)