Material Finishes

FINISHES, PLATINGS, AND COATINGS FOR WAVE SPRINGS AND RETAINING RINGS

After selecting the appropriate material for your application, adding a finish, plating or coating may be necessary to meet your application requirements. These additional processes can improve the function, look, and performance of the part.

BLACK OXIDE

MIL-DTL-13924, Class 1This finish provides a flat black appearance that is generally used to alter cosmetic appearance instead of an improvement in corrosion resistance.

CADMIUM PLATING

Cadmium Plate, AMS-QQ-P-416, Class 2, Type I
Cadmium Plate w/Chromate Dip, AMS-QQ-P-416, Class 2, Type II
Cadmium plating is used on carbon steel to increase the corrosion resistance of the product. The process of cadmium plating spiral retaining rings is costly and subjects the ring to the possibility of hydrogen embrittlement. Smalley offers stainless steel as the preferable option to cadmium.

OIL DIP

This is the standard finish for all Smalley products produced from carbon steel. The oil provides resistance to corrosion in transport and normal storage. The oil dip finish should not be considered a permanent finish.

PASSIVATION

AMS 2700, Method 1, Type 2, Class 3
Passivation is an optional cleaning operation for stainless steel. It provides a bright finish and increased corrosion resistance. Passivation dissolves iron particles and other substances, which have become embedded in the surface of stainless steel during production. If not dissolved, these foreign particles could promote rusting, discoloration or even pitting.

The corrosion resistance of stainless steel is due to the thin, invisible oxide film that completely covers the surface of the ring and prevents further oxidation. Removing the contaminates prevents breaks in the oxide film for optimum corrosion resistance.

VAPOR DEGREASE / ULTRA SONIC CLEAN

This is the standard cleaning and finish for all products manufactured in stainless steel. The process removes oil and other organic compounds from the material surface by use of a degreasing solvent, which is forced between the turns of the part with ultrasonic waves.

VIBRATORY DEBURR / HAND DEBURR

Although all circumferential surfaces and edges of Smalley products are smooth, sharp corners can be present on the gap ends due to the cut-off operation. To break the sharp corners and achieve a smooth surface finish, parts may be either vibratory or hand deburred to meet your specifications.

ZINC PHOSPHATE

MIL-DTL-16232, Type Z, Class 2
This finish is sometimes referred to as “Parkerizing” and appears gray-black in color. The corrosion resistance of phosphate is superior to black oxide but inferior to cadmium plating or stainless steel. Phosphate cannot be applied to stainless steel.

ZINC PLATING

Zinc Plate, ASTM B633, Type V, Fe/Zn 5, SC1 (Colorless)
Zinc Plate, ASTM B633, Type VI, Fe/Zn 5, SC1 (Colored Chromate)
Zinc plating is used on carbon steel to increase the corrosion resistance of the product. It is sometimes used as a more cost-effective alternative to other plating options or stainless steel. Smalley’s standard
zinc platings, Type V and Type VI, are RoHS compliant. The thickness level of the plating is controlled by the service condition number (SC Number), which should be designated by the customer. Zinc plating does not guarantee coverage between the turns of multiple turn rings and springs. (The process does subject the part to the possibility of hydrogen embrittlement. We offer stainless steel as a preferable alternative.)

HELPFUL LINKS

• Contact a Smalley Engineer to determine the best material for your application
• View Materials Table for more specifications on our common materials
• Read Blog: How to Control Corrosion: Material Selection for Rings and Springs
• Read EBook: Material Selection Guide