The degree of corrosion resistance of a stainless steel alloy is a function of the alloying composition, heat treatment, internal stresses and passivation treatment. An example of this phenomenon is free-machining stainless steel which has notably less corrosion resistance than stainless steel due to the higher concentration of sulfur and phosphorous that imparts the desired machinability of the grade.
As a general rule, the higher the nickel and chromium content in the alloy, the more corrosion resistance it will have. In addition, APT can meet the requirements of any company-specific nitric or citric acid stainless steel passivation methods. Our company also provides passivation of stainless steel to the Carpenter A-A-A process to passivate difficult stainless steel alloys including high-sulfur free machining or alloys as well as high chromium alloys such as stainless reference: A-A-A Passivation Methods article in our Metal Finishing White Papers section.
Inhibited passivation solutions are available to maintain bright surfaces of stainless components such as machined faces and centerless ground or stainless steel shafts. Unfortunately, very few part prints indicate the specific method to be employed.
Advanced Plating Technologies provides full in-house testing services to certify the performance of our stainless steel passivation including high humidity, salt spray per ASTM B, potassium ferricyanide. Appendix X1 and Appendix X2 give some nonmandatory information and provides some general guidelines regarding the selection of passivation treatments appropriate to particular grades of stainless steel. This specification makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria for any particular application or class of applications.
These tests include the following practices:. Note 1: Free iron denotes iron present on the surface of the parts, including but not limited to iron contamination, iron-tool marks, residual-iron salts from pickling solutions, iron dust, atmospheric exposure, iron deposits in welds, embedded iron, and iron oxide.
The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may result in non-conformance with the standard. Ray Kremer Stellar Solutions, Inc. The ASTM has established certain criterion to achieve consistent product quality in the metal finishing industry. Able Electropolishing provides metal passivation services that meet the ASTM A standards, as well as other finishing treatments that improve the corrosion resistance of stainless steel and various other alloys.
If you do not specify, they can use whatever they want, even ways that are not in any of the specifications! I was looking at this thread and had this question Precision Machining Technology Show. Passivation is the overlaying of a substrate or base layer with another metal.
In the ASTM A and the nitric acid concentrations mentioned must be percentage by volume of a reagent of 67 wt. By meeting standards set by the ASTM and other organizations, we can ensure consistently-high quality for a broad range of metal parts across many industries. Specific treatments are however also specified.
Stainless Steel Products. Standard Specification. Stainless Pipe Dimensions. Material Grades. Chemical Composition. Mechanical Properties. Technology Flow chart. Range of Applications.
Producing Equipment.
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