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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Hard chroming of plates..
OK guys.. Hopefully someone can help me out here..
We have these 4140 plates for a customer. On the print they call out for ..007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. |
#2
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Hard chroming of plates..
"tnik" wrote in message ... OK guys.. Hopefully someone can help me out here.. We have these 4140 plates for a customer. On the print they call out for .007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. Are you sure your customer is not missing a zero? Hard chrome coatings are typically 1/10 that thickness. As plating gets thicker internal stresses buiuld up and can cause it to delaminate. Although, I am searching the web and see that there is a process called "hard chrome build up" where some vendors advertise up to 1000 microns (.039") You might want to try lapping instead of grinding. It is much easier to control on very thin coatings. Also makes flatter and finer finishes than grinding. |
#3
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Hard chroming of plates..
On Wed, 18 Aug 2010 16:43:21 -0400, tnik
wrote: OK guys.. Hopefully someone can help me out here.. We have these 4140 plates for a customer. On the print they call out for .007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. ========== What is the function of the chrome plate? Depending on the function, you might consider TiN coating. Very wear resistant and you should not need to grind at all. for general info see http://en.wikipedia.org/wiki/Titanium_nitride for some suppliers at random see http://www.brycoat.com/ http://brycoat.com/pvd-tin.html http://www.swiss-tekcoatings.com/tin...-coatings.html http://www.ionic-tech.com/?gclid=CJP...Fc9N5QodFCf7ZQ many more on web. -- Unka George (George McDuffee) ............................... The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953). |
#4
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Hard chroming of plates..
On Aug 18, 2:43*pm, tnik wrote:
OK guys.. Hopefully someone can help me out here.. We have these 4140 plates for a customer. On the print they call out for .007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. Sounds like bad design. Electroplating will be hard to get even coating at that thickness, field strength at corners causes extra build up. It's waaay too thick, like the other poster said, hard chrome is used in THIN applications. If the customer needs a hard face, how about one of the flame-sprayed coatings, or TiN? Bubbles in plating is a process control problem and chrome doesn't stick very well to steel without an intermediate layer or two, usually copper and nickel. Electroless nickel would stick well, if it's just a decorative thing. It all comes down to what the hard chrome is supposed to do. Stan |
#6
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Hard chroming of plates..
On Aug 19, 9:04*am, tnik wrote:
On 8/19/2010 8:51 AM, wrote: On Aug 18, 2:43 pm, *wrote: OK guys.. Hopefully someone can help me out here.. We have these 4140 plates for a customer. On the print they call out for .007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. Sounds like bad design. *Electroplating will be hard to get even coating at that thickness, field strength at corners causes extra build up. *It's waaay too thick, like the other poster said, hard chrome is used in THIN applications. *If the customer needs a hard face, how about one of the flame-sprayed coatings, or TiN? *Bubbles in plating is a process control problem and chrome doesn't stick very well to steel without an intermediate layer or two, usually copper and nickel. *Electroless nickel would stick well, if it's just a decorative thing. *It all comes down to what the hard chrome is supposed to do. Stan The chrome is there for wearing against wood in a big mulcher. I've talked to a couple of people today, and with your guys suggestions I have a small arsenal that I can go to the customer and try to do something different.- Hide quoted text - - Show quoted text - Hardening the 4140 isn't enough? Wear plates should be readily changeable, anyway. Might be a more abrasion resistant alloy would work better(and cheaper). Plating these days isn't cheap. Stan |
#7
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Hard chroming of plates..
On Aug 19, 11:50*am, wrote:
On Aug 19, 9:04*am, tnik wrote: On 8/19/2010 8:51 AM, wrote: On Aug 18, 2:43 pm, *wrote: OK guys.. Hopefully someone can help me out here.. We have these 4140 plates for a customer. On the print they call out for .007 - .009 thick chrome on one face finished. So we try to get the plater to put .004-.005 over so we can grind them flat. We tried having them only putting .001-.002 over, but that never worked out well. The plater we use is having a really hard time getting a consistent buildup all over the plates.. And recently we are seeing a crap load of bubbles, and some of the plates are actually flaking on the edges. So, here is two questions to the more knowledgeable than I. 1) Is there any other type of coating that is comparable or better than chrome, that we could suggest to our customer, that would save the time and anguish of us grinding, finding out the chrome is bad, and sending the plates back to get more added? 2) If it's the chrome plater that is actually at fault, does anyone know of a good plater that is in Florida, preferably near central, but not required.. We can UPS the plates. I'll even send them out of state if need be.. Anything is better than the situation that we are in now. Sounds like bad design. *Electroplating will be hard to get even coating at that thickness, field strength at corners causes extra build up. *It's waaay too thick, like the other poster said, hard chrome is used in THIN applications. *If the customer needs a hard face, how about one of the flame-sprayed coatings, or TiN? *Bubbles in plating is a process control problem and chrome doesn't stick very well to steel without an intermediate layer or two, usually copper and nickel. *Electroless nickel would stick well, if it's just a decorative thing. *It all comes down to what the hard chrome is supposed to do. Stan The chrome is there for wearing against wood in a big mulcher. I've talked to a couple of people today, and with your guys suggestions I have a small arsenal that I can go to the customer and try to do something different.- Hide quoted text - - Show quoted text - Hardening the 4140 isn't enough? *Wear plates should be readily changeable, anyway. *Might be a more abrasion resistant alloy would work better(and cheaper). *Plating these days isn't cheap. Stan- Hide quoted text - - Show quoted text - Just thought of another thing, with regard to bubbles. Are these plates getting any sort of post-process heat treatment to remove hydrogen? If not, that's a BIG problem. Look up "hydrogen embrittlement". The thicker the plating, the more problems you get with it, too. All those freed protons in the plating bath go somewhere and mostly right into the workpiece. Stan |
#8
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Hard chroming of plates..
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