I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.

Am I wrong? Is the supplier suggesting something reasonable? I am a machinist by trade, and an engineer by default, not a metallurgist. I need expert advice from someone who really knows their steel castings.

I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.

Am I wrong? Is the supplier suggesting something reasonable? I am a machinist by trade, and an engineer by default, not a metallurgist. I need expert advice from someone who really knows their steel castings.

Well, to put it bluntly if the customer specifications are No cold shut's and the supplier has these spec's available to them and have a contract with you, then no, they are not allowed.

Did they PPAP/FAI the casting process prior to a production run? Ususally they prove the mold and casting process fisrt on a prototype piece in conjunction with a casting program (Magma) which shows the optimum pouring solution.

Options)

1- Get the customer's deveiation request in writing to allow the supplier to grind

2- The supplier has to eat the costs of the scrap parts and must involve SQA and their process engineers to figure out a solution.

I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.

Am I wrong? Is the supplier suggesting something reasonable? I am a machinist by trade, and an engineer by default, not a metallurgist. I need expert advice from someone who really knows their steel castings.

For non-casting process Covers, here is a definitinion:

COLD SHUT
A defect produced during casting, causing an area in the metal where two portions of the metal in either a molten or plastic condition have come together but have failed to unite, fuse, or, blend into a solid mass.

Source: The Metal Dictionary (http://www.metal-mart.com/Dictionary/dictleta.htm).

Stijloor.

I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.

Am I wrong? Is the supplier suggesting something reasonable? I am a machinist by trade, and an engineer by default, not a metallurgist. I need expert advice from someone who really knows their steel castings.

My opinion: Make the supplier remelt new castings and I would also issue a Corrective Action. Have the supplier look at their processes and see if it is a process failure and provide root cause.

I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.

Am I wrong? Is the supplier suggesting something reasonable? I am a machinist by trade, and an engineer by default, not a metallurgist. I need expert advice from someone who really knows their steel castings.

What type of product are you producing?

Years ago, I used to be involved in valve manufacturing and cold shuts/cold weld were absolute no no!!!

Technically, you can make a sound casting by welding.

I would ask the supplier to perform pull test on a samples. Let them see the consequence of sending defective material.

I would also ask them to submit xbar/r charts on temp control with every shipment. I am sure they don't have one. Once they start collecting data, the problem will go away.

You need a permanent solution and not a temporary fix.

I am dealing with a supplier who wants to grind away the visible indications of a "cold shut" on steel castings that they supply to us. Our customers specifications say that "cold shuts" are unacceptable for any reason. The supplier wants to avoid scrapping hundreds of parts. My concern is that a "cold shut" is likely more of a defect than a visual defect. I believe it weakens the casting, and that grinding away the visual effect would only disguise the fact of a compromised casting.


If the outright ban on cold shuts was "flowed down" to your supplier, then you have your answer already. It doesn't make any difference whether the defects in question actually compromise the structural integrity of the parts or not. Unless you're prepared to ask your customer to accept the defects, and they agree, you really don't have much choice.

I didn't provide enough information. A little extra background.

For better or worse my employer has gotten into supplier relationships going both ways with China. We buy chinese castings, and we sell finished machined products to China. The relationships are handled by a distributor who also takes care of CAPA, and translation issues.

Whatever the corrective action is (and there will be one), it is not likely to be anything as sophisticated as asking for data.

The customer's spec allows rework in tightly defined situations. If the wall thickness (after rework) is within a certain tolerance, and the cold shut indication is completely removed they can be accepted on a "deviation".

We have used a die grinder to grind the areas back to parent material and are having a lab non-destructive test for micro-cracking. My concern is that the casting is **** anyway. It turns out that there is more than one indication area. I am in a bad spot because shipments will be missed if we can't rework. I really need to know if cold shuts compromise the metal structure.

I really need to know if cold shuts compromise the metal structure.

Based upon this definition:

COLD SHUT
A defect produced during casting, causing an area in the metal where two portions of the metal in either a molten or plastic condition have come together but have failed to unite, fuse, or, blend into a solid mass.

In my opinion, it would affect structure and strength. You have a lack of material joining together which could cause failure under stress. I am not a metallurgist so I could be way off base.

Hi,
I have been dealing with China, and steel casting in low and Medium steel.
In low carbon steel and medium it does effect the fatigue strenght of the material all over.

You can anneal the medium (above 19% C) and control parts after casting.

There is only two compainies that I deal with around Shanghai, that do Xray testing and have a certified lab. The low carbon steel you can anneal but really does not help that much.

One thing that I have found besides Xraying is using a dye penatrent which is good up to 1/8" deep or Mag partice for deeper disconuities. This will help in small pump casting ect.

Just remember the effects of mass will increase in parts above 4" in LC, and
8" in above MC, casting. Hope this is answer for you.

Run the casting thru a wet mag partice belt line at 100% to be safe.

We are having two representative parts magnetic particle tested on Monday. If they are OK we will be just in time to ship that afternoon. If they are not OK then it is case closed for the supplier.

Thank you everyone for the input.

Rich

:topic:No scolding here, just a comment. The situation here is fomented by the lack of complete Contract Review and subsequent assurance by all concerned parties they know and recognize what constitutes a nonconformance and allowable "repairs."

As an owner of a contract machining company, I played a lot of CYA when a customer wanted to dictate a source of supply for ANY material (casting, forging, bar stock), simply because so many purchasing departments were fixated on PRICE rather than QUALITY. Often, we simply refused a job if the suggested/dictated supplier didn't measure up to our own standards.

If you need an interpreter just to "talk" or write to a supplier, how can you possibly be sure the supplier has a complete understanding of what your requirements are and how to conform to them?

Frankly, the whole deal starts to smell like melamine in pet food - somebody is cutting corners and the perpetrators are hoping a little grinding will make the issue go away (like painting walls gray to hide the grime.) Good control over the casting process can easily reduce or even eliminate the instances of cold shut on most simple castings. If the casting isn't simple, the manufacture of a good one may simply be beyond the capability of the current supplier. It would not be the first time an inept supplier promised more than he could deliver.

If it's a true cold shut, I'd worry about weakened wall structure that might erode prematurely or fail catastrophically depending on the pressure and media these valves experience in service. Magnaflux and dye penetrant are good methods to check for clean-up, but still might not guarantee valve quality.

Funny, I recently had a short stint of employment at a cast iron manufacturer who casts ductile and gray iron castings in the US. They entered into a supply agreement/outsourcing agreement putting them between the US customer and the Chinese foundry as a middleman. The original trial castings supplied were good quality ductile iron. The ones we ran into during my tenure were a mystery - our customer complained regarding machining, and when we checked, we'd see good quality ductile next to good gray iron - definitely not decomposed ductile iron. Our best guess was possibly using gray iron scrap to cool a ladle of ductile iron, leaving remaining fingers of gray iron in a ductile casting. We were close to shutting down the customer's pump line (automotive related) for lack of castings.

The customer's purchasing agent had secured his bonus for outsourcing castings to China and moved on before the problems hit. I've no idea how this worked out, as I returned to my prior employer (the situation I inherited did contribute to my decision to return when I got a call from them asking if I was interested in returning.)

<snip> The customer's purchasing agent had secured his bonus for outsourcing castings to China and moved on before the problems hit.

A classic example of "what's rewarded gets done" without regard to the unintended consequences. :mg:

Stijloor.

, we'd see good quality ductile next to good gray iron

Wow, if they could do that on purpose, they could get rich!
Maybe it was actually elegant engineering - a dual phase structure?
Just kidding. If I set out to do that on purpose, I'm not sure I could!



1) lack of complete Contract Review and

2) know and recognize what constitutes a nonconformance and allowable "repairs."

3) fixated on PRICE rather than QUALITY. .

Wes, you beat me to it.

A topic near and dear to my heart as the foundry I work at gets ready to close in the face of low price offshore castings, brace yourself while I unload.

1) Failure of contract review indeed. This is just typical boilerplate text by the buyer to trap the unwary seller. I was trained to reject anything that said "no" or "none" in favor of suggesting a measurable level. Things like no leaks, free from harmful defects, sound castings, no cold shuts are meaningless and should have been raised as issues for negotiation. There is no "NO" in the real world.

The foundry should make the customer design engineer earn his money and call out meaningful measurable specs based on what he really needs, not wishful thinking. And of course the only time you can do this is up front, once you accept an order you are bound by the contract, and an apparently long dead business tradition called "honor".

Gee, maybe those ISO 9000 guys put contract review in there for a valid business reason?

The foundry failed big time in contract review and may have to eat these parts.

2) Friends don't let friend drive drunk. The buyer failed by going for the boilerplate PO gotcha instead of working with the foundry to make a producible casting. So after the buyer makes the foundry recast, do they really think the replacement castings will be any better? The foundry has lost more than it could ever profit from on this order, how keen do you think they will be to make good? So the buyer may win this battle but will surely lose the war.

3) How much has it cost the purchaser to "save money" buying these low cost castings? Please factor in late delivery, all the effort to contain this problem, risk of accepting bad castings with possible long term warranty consequences, dissatisfied customers, and so on.

I double dog guarantee any money the purchaser thought they "saved" on the low price has cost them 10 times the hoped for saving.

Price is not equal to cost, and buyers have to keep learning this over and over and over.

The really sad part is I bet the buyer got a nice fat bonus based on the "savings" and has washed her hands of this quality problem.

This is not a China bash. The best of the Chinese foundries are as good or better than anyone else. Chinese engineers are talented, dedicated and they want their piece of the pie. Good on them, they deserve it.

This is a tirade against low cost suppliers and the people who buy from them. If you get 3 bids within 10% of each other and a fourth at half the price, come on - you know, the low bidder missed something, doesn't know what they are bidding, or has no intention of meeting your requirements.

Of course this has been said here before, much better than I ever could, see Sales the Root of Quality Disasters (http://elsmar.com/Forums/showthread.php?t=10180&highlight=sales+root+quality+disasters&page=2)

My father was a foundryman, so I posed this question of him. He said that cold shuts usually come from an interupted pour, or from the metal being too cold. You certainly could grind off the cold shut, but you'd want to be darn sure that the defect doesn't go all the way through the wall of the casting. Certainly grinding would make the surface of the casting look smooth - but if it was an interupted pour, there would be a crack all the way through the casting.

The cause is now known. The pour was too slow, and it is a true cold shut. The castings are not acceptable by the standards of the end user. These things were all spelled out in the contract review/purchase order process. As noted by a previous poster, we recieved sample parts during the original acceptance process, and approved them. The quality of the latest shipments has changed significantly from the quality of what we approved. There now turns out to be evidence that the distributor's agent in China changed at least one supplier sometime in the last year. Someone mentioned that this is a case of someone cutting corners. They hit that one right on the head. The good news is that the end user is the one who stipulated that these suppliers be used. Their motivation was to save on price. It was stated to us that these castings could be purchased finish machined from China for what it used to cost us just to have them cast here in the US. Other cost factors were not considered. Now the true cost is becoming apparent to them.

Comment from my father:

True Experience that one has to pay the piper for such decisions.

Jerry Call Ex-Director Foundry Society would love to see this if you wanted to share such with him and not show persons involved.
jcall (at) afsinc.org

Bob Prevette