Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
Plating/finishing AISI 1095 spring steel
Q. I am designing some AISI 1095 steel springs for use in holding down a workpiece in a machine that works in a humid but non-condensing environment. The springs will be formed in the annealed condition and then hardened. I have 2 questions:
1) What are the top 2 or 3 platings that I could use on these hardened springs in order to prevent any rust? Bright finish is desirable but not necessary.
2) Do I need to limit the maximum hardness to get a good durable plating finish that will not allow rust and which will not be permanently discolored by finger prints, hand oils, etc.?
Thanks,
- Bettendorf, Iowa
2003
A. The most common coatings for springs are the following:
a) zinc phosphate + oil
b) electroplated zinc + chromate conversion coating
c) zinc phosphate + organic coating (usually cathodic electrodeposition epoxy) Zinc phosphate + oil has the least corrosion resistance, followed by electroplated zinc, and finally zinc phosphate + organic.
Springs that are electroplated require hydrogen embrittlement relief, which usually involves heating to a temperature of 190-220 °C for a specified period of time. The exact temperature and the specified time depend on the tensile strength/hardness of the steel. If the steel has been tempered below 200 °C (usually hardness of > 400 HB or 40 HRC) then the relief temperature is more like 115 °C for 8 hours minimum. SAE USCAR 5 and ASTM B850-98 are good documents to reference when it comes to hydrogen embrittlement relief.
- Michigan
2003
Multiple threads merged: please forgive chronology errors :-)
Finish for AISI 1095 blue tempered steel - flat spring application
Q. We are going to be using AISI 1095 sheet material to make a flat spring. As part of the manufacturing process, we will be putting a thru hole in the spring as well as shaping the outside. This spring is used on a medical instrument and it most likely will experience exposure to a bleach / water cleaning solution (in case of a blood spill). The spring is used in a latch operation and will undergo about 4-6 actuations a day when loading or unloading our treatment kit - so the cycles over life are not that huge (3,000 would be a high number).
During a design review, the question came up about corrosion protection on the spring and particularly the edges. The spring itself is about 0.125" wide x 0.75" long x 0.020" thick. The spring undergoes about .060" deflection during it's operation and is sliding over a surface that has an electroless Nickel finish.
The reason we have chosen 1095 is because of its high yield stress (>200 ksi). We are operating around 150 ksi max stress.
What options do I have for putting a finish on this part? Is electroless Nickel and option? There was a concern that the plating may crack under the deflection stress. I want to make sure I don't affect the temper of the spring during the finish process.
Product design engineer - Rochester, New York USA
October 13, 2009
A. If exposed to bleach 1095 will rust very quickly. Electroless nickel, if thick enough (.001" min) will be reasonably rust resistant and can be expected to flex some.
Make certain that the parts are closely inspected after plating to verify that adhesion of the nickel is good.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
October 14, 2009
Jeff,
Thanks for your reply. I was thinking about EN but was concerned about the flex. I will make sure we have a note on our print to inspect the finish.
Product design engineer - Rochester, New York USA
October 20, 2009
Plating 1095 spring steel for fresh water lake area protection
Q. I need to plate a 1095 spring steel part that is in the shape of the letter W which holds two plastic decking panels together for a dock application. I tried zinc. I tried nickel and I tried powder coating. The zinc or nickel rusts on some acidic lakes. The powder plating chipped off is a few places. Should I use a combination of the two? Please be specific with your suggested process. Would the finish be the same if the application was near salt water?
Jack Poucherdesigner - Harris, Minnesota, USA
April 26, 2010
A. Unless you can use a corrosion resistant alloy, corrosion is going to be a problem regardless of the coating. Electroless nickel, not less than .001" thick, or hot dip galvanizing are likely to be the best choices. If coated correctly, I'd guess a life of a few years.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
April 29, 2010
A. Consider fabricating the part out of monel or a high nickel stainless.
James Watts- Navarre, Florida
April 29, 2010
Plating 1095 spring steel to resist deflection
October 26, 2011Q. Hello,
Intro:
I have a design of an cantilever flat spring (complex form) with a deflection more than .070'' with a load between 50 and 100 pounds. The spring clamp-in, clamp out regularly.
The flat spring is short (+o-) 2" length X .5" width X .050 thickness) and the choice of material so far is 1095 spring steel (support 238,000 yield strength) but forming annealed and only after the heat treatment to obtain 49 RC, have to support regular abrasion and corrosion (outdoor device)
Question a): What kind of plating we have to add if we looking for a metal finishing like chrome or similar (electroless nickel, zinc or others) to resist at the regular deflection and be sure there is no micro cracks and resist at long term at the corrosion ?
Question b) If is not possible do we have to change the spring steel material, what do you suggest ?
Thanks
Andre
inventor - Quebec CANADA
A. You might try an electroless nickel product which can have various solids mixed in the plating as it is being plated -- additives such as teflon and some kind of super hard ceramic (but I forget what) which makes the plating abrasion resistant.
Tim
prototyper - Orlando, Florida, USA
November 9, 2011
Q. I am looking for a plating/coating that can be applied to 1095 Spring Steel, ASTM A682 [withdrawn]/ASTM A684. I know that zinc and nickel type platings can cause hydrogen embrittlement in most spring steels. The type of plating is purely for protection against rust and the application of the spring steel is being used as a keyed washer on a medical monitor mount used in the OR.
Bernard MossSenior Designer - Mentor, Ohio, USA
February 10, 2015
A. Hi Bernard. It is not just the plating process, but the acid-based prep steps (and cathodic electroplating, if employed) that cause hydrogen embrittlement. As an alternate you might consider blasting and mechanical zinc plating. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 2015
Q. Please tell me what/how do you clean 1095 Steel prior to plating?
Cindy Poole- Rochester, New York USA
July 24, 2015
A. Hi Cindy,
You need to add a lot more information before anyone can help you.
There are whole books written on pre-treatments of materials so to give you a concise answer is all but impossible.
Possible (and this is nowhere near exhaustive) techniques will include degreasing (both or either solvent or aqueous), alkaline cleaning, acid cleaning, abrasive blasted with any number of abrasive types, acid pickles, alkali pickles, derusters, metal strikes, such as nickel strike or copper strike.
A combination of cleaning methods will be used, but all depends on what you want as your finish plate, gold, palladium, zinc, cadmium, copper, nickel, chrome just to name a few!
Aerospace - Yeovil, Somerset, UK
August 3, 2015
Q. I am looking for input on a 1095 spring steel that is hardened to HRC 56-60. We are barrel zinc plating with clear chromate and we are struggling with corrosion protection. We aren't even passing 16 hours to white.
in your opinion, could a faulty cleaning process, say excessive electro clean or muriatic acid exposure, impact salt sprayS performance?
- mpls, Minnesota>
May 9, 2016
A. White corrosion is the zinc corroding and would have little or nothing to do with the prep steps.
It is your conversion coating that is failing. Check concentrations, time and temperatures plus the final rinse step .
If all of this is ideal, contact tech services of your conversion coat.
- Navarre, Florida
May 10, 2016
Q, A, or Comment on THIS thread -or- Start a NEW Thread