PLATING ON LEADED STEEL
Q. Our shop plates a number of different steels using a zinc cyanide plating bath. One type of steel, 12L14, a leaded steel, continually gives us problems with blisters and peeling. Do you have any suggestions as to how we can solve this ongoing problem? L.F.
A. Leaded steels like 12L14, which contains 0.15 –0.35% lead, are produced to allow enhanced machinability. Essentially, the lead smears on the part surface during the machining process and acts as a lubricant. For platers, the problem with these leaded steels is simple: If the lead is not completely removed from the surface, you will not obtain a satisfactory deposit.
The following cycle should remove the lead on the surface and give you good results:
1) Soak clean to remove oil and grease.
2) Clean anodically at a current density of 90–100 ASF in a strong alkaline cleaner.
3) Dip in an acid such as acetic, fluoboric or glycolic acid. Proprietary acids are also available for this purpose.
Rinse thoroughly between each step.
A primer on this inexpensive and highly efficient process.
Our expert, Art Kushner, says yes, you can color stainless steel, but it is not a process that is typically performed in a plating shop. Read more about his answer.
Masking is employed in most any metal finishing operation where only a specifically defined area of the surface of a part must be exposed to a process. Conversely, masking may be employed on a surface where treatment is either not required or must be avoided. This article covers the many aspects of masking for metal finishing, including applications, methods and the various types of masking employed.