It looks like I'm going to have to have some portions of the side sheets of a firebox replaced. When you read my question, you'll see that it is obvious that I won't be doing the work myself. But, at this point letting out is contract is somewhere in the future, so I don't have a contractor to ask. This is an oil-burner, and the area along the top of where the fire brick goes doesn't look really good.

Here's my question: The ALCO blueprints for this locomotive say that the sheets in question are 3/8" thick. I have some steel on hand that is 13/32" thick; 1/32" thicker than called for. Could this 13/32 material be used, or is 1/32 too much of a difference? And, the sheets that look "ok" at this point, may be somewhat thinner than 3/8. We haven't done our ultrasound testing yet.

Thanks in advance for your opinions.

Firebox sidesheets were generally thinner because that is where the heat transfer occurs. Many loco builders took wear and thinning into consideratin when designing the firebox. Do your ultrasound first and then based on your calculations determine if they need replaced.

Assuming you are planning on a welded repair, a more important question is whether or not the existing steel in the firebox is weldable. You will want to send samples of the removed material to a laboratory to get an analysis of the elements in the steel. Carbon content is very important and should be no more than .28%.

1/32" should not be a problem, but be sure the material you are using is of proper specification and grade for the job.

S.O.

Until you run your calculations you won't know what the minimum critical thickness is for the original sheets. You may not have to replace anything based on thickness alone - just one variable to be considered. There are a lot of good and talented people in your region with the legitimate knowledge and experience to help you out, and more that just think they do and will be happy to take your money, so please carefully choose a good consultant to guide you through this process.

dave

May we here at Wasatch take a few minutes to provide a few time saving and money saving tips to your project.

1. As has been mentioned by Dave L. PLEASE do all of your Ultrasonic studies and create a working copy of your Form 4 FIRST. We see this mistake made so many times! We end up helping groups that "thought" they had problems, only to find that what they did on their own.....was "OK" to start with. They overlooked things that really needed to be fixed and were left with a lot of money spent and no where closer to an end goal of being able to operate. The key is; Do your Ultrasonic Study and working copy of a Form 4 FIRST.

2. Even though you have plate on hand, you really should ensure that your plate is boiler quality. Do not put standard A36 plate in a fire box....or anywhere in the pressure retaining boundaries of your boiler for that matter. Consult with a boiler maker that can ensure that you have the right plate for the job. (Side note: A 3/8 inch thick piece of steel is actually thicker than 3/8 when you count the mill scale that could be on the plate. The amount of usable steel is 3/8).

3. Once you have a working copy of your Form 4, consult with somebody on this page that you feel you can trust. For example, Kelly Anderson hangs out on this page along with his side kick Rick M, they will answer your questions (Strasburg Railroad). Gary Bensman (Diversified Rail Services) hangs out on this page, he will answer your questions, Matt Janssen of Vapor Locomotive hangs out on RYPN....the list goes on and on. I am personally more than happy to answer your questions. If I can help prevent any costly mistakes, I am here to do it. Most, (I say most for a reason) of the "contractors" that hang out here on RYPN are more interested in helping you save money, than spend it. If you need help finding other contractors, ask around, you will find them.

4. Find somebody that you can trust and have them go over this project with you. This "somebody" needs to a person who has done the work with the FRA, has a good working knowledge of the industry and has done the work. True, there is a lot you may not want to hear. However, if you know up front what you face, you will be more prepared to make good decisions. As noted above, most of the contractors out there are interested in teaching and helping....not just walking away with money. Go out and find them!

I would encourage you to keep this topic going. You may find many others who have some good advise. We here at Wasatch RR wish you the very best of luck. If we can help, let us know!

John E. Rimmasch
Wasatch Railroad Contractors

wrrc.us

John,
Sounds like the saga of Georgetown Loop #12 and the CHS. Now that the #12 is operational, the client is the government therefore all the information is public record, can you fill us in on some of the details? Perhaps in another thread?

Matt

ASME SA-285 is a pressure vessel grade steel for firebox use. I used it in a 18 inch gauge 2-6-2 a friend of mine and I built. The first pass for welding was done with 7014 rod and the following passes were done with 7018 rod.
Roger Mitchell
Master Mechanic/Vice President
Fort Collins Municipal Railway

Recently when requesting a quote from a vendor for SA-285 Grade C plate, they attempted to direct me instead to SA-515 Grade 70. We have always used SA-285 in all of our firebox repairs, so it seemed odd to me that someone would suggest a different type of steel. After doing a little further research, I came across some discussion in a boiler and pressure vessel engineering forum that indicated that presently produced SA-285 Grade C is not equivalent to the SA-285 Grade C Firebox Quality steel that is described in the old boiler codes. In this forum, they stated that indeed SA-515 would be an equivalent material substitution for SA-285 Grade C Firebox Quality. I also noted that SA-515 is listed in the draft 2010 edition from the National Board.

My question is this, has anyone ever used anything other than SA-285 for firebox sheet replacement? If so, what kind of results have you seen? We are not necessarily interested in deviating from our past practices, but would simply like to understand the current thought behind all of this.

Rich,

One thing to keep in mind with the SA-515/516 Grade 70 plate. It is 70,000 lb tensile strength as a minimum. I have seen grade 70 plate with a tensile strength as high as 81,000 psi. The SA-285-C can be gotten in the range of 56 - 64K tensile very easily. That will make your staybolts a lot happier.
Finding SA-515/516 in that tensile range is very difficult at best.

Rick

I'm very interested/curious about this! I'd like to know more.

Thanks,
Mark

I would need to go back to see if I could find the original discussion, but according to my notes, SA-285 Firebox Quality steel was fully deoxidized with silicon killing. I'm not a metallurgist so I'm not sure exactly what this means. I'm wondering if there have been minor changes in the manufacturing process over the years that led to the designation of 'Firebox Quality' being dropped? Could this be a possible explanation for the anecdotal stories we've heard that today's steel is not as good as the steel produced years ago? Is there even any validity to the statement that presently produced SA-285 Grade C is not equivalent to the SA-285 Grade C Firebox Quality steel?

Are there any metallurgists around here that can shed some light on this?

Older steels are not exactly better in general, nor are newer steels worse. It depends on the intended application. Modern applications tend to push materials to higher strengths to save weight and use less material. This is implied in the previous posts. It is harder to find the softer, forgiving, pliable, low carbon steels of the past. That sort of alloy is represented by the SA-285 gr C spec. Even it is a bit on the strong side.

I am reluctant to endorse using the 7000 series welding rod with that alloy. You will get a very strong weld that will dominate the surrounding metal and create a stress concentration in the heat affcted zone. A better match is the 6000 series rod.

Killed steels are simply treated at the steel mill to remove dissolved gases in the molten metal. Silicon is an effective deoxidizer. Without this treatment, when the "heat" of molten steel is "teamed" into ingot molds it will 'fizz" with the disolved gasses coming out as the metal cools. Adding silicon to the molten alloy causes much of the oxygen to combine with the silicon to form silica and join the slag on top. The teamed metal now just sort of sits still in the ingot mold, no fizz or froth. It acts dead or "killed". This results in a more homgeneous plate with fewer inclusions. It will also have more ductility and a bit less strength. This is goodness and means more tough and forgiving behavior. That is what you want in a firebox that is being thermally tortured everytime it is fired up.

Enough armchair metallurgy,

Fred Feiertag
retired metallurgist

I really liked the explanation about the metal as posted above. Great education!

We here at WRC agree 100% with the use of filler metals.....may I expand that portion of the above post.

What we see as a common mistake is groups that want to use 7018 as the primary filler metal. I ask often, "why, 7018?" Answer; "Because it is stronger!"

We need to keep in mind that the old base material (to which we will weld a new sheet to in the fire box, for example) has a Tensile Strength of 55,000 lbs to say 60,000 lbs. Now, say you get a piece of 516/70 which Rick M has noted can be as high as 81,000 lbs Tensile. We now have a variation of up to 30,000 lbs between the original metal and the new metal. ( that is a lot right?)

I agree that the use of a 60,000 lbs. filler is the best option, not a 70,000 lbs. filler. I was so interested that I even sought after a manufacture of a 6018 for use in historic boilers. ESAB agreed to make it...if we purchased 20,000lbs of it! If we could convince the industry that we need a 60,000lbs. Low/Hyd filler and if we knew we could sell all 20,000 lbs. I would be the first one to buy it!

Now mistakes made; I have been in a fire box where new SA516/90 (90,000 lbs) was used with old original plate. The filler metal.......E11018....yea, that is 110,000 lbs filler metal. Double that of the base material.

"Why did you do that?" Answer. "It is what we do in the power plant industry.....required by code....it is what you have to do!"

My response......."what?"

Anybody interested in E6018? It would be great!

Consider your filler metals well before use.

John E. Rimmasch
Wasatch Railroad Contractors

wrrc.us

Everyone: Thanks for all the information. The material I have on hand is stamped "A-285-C", so it appears to be the right stuff. Someone wanted to buy it, so I'll probably wait until I get the ultrasound done to see how much I might need. Then sell the remainder. Thanks again.

Jim Baker

Hang on to it and its pedigree, Jim. You will never run out of opportunities to replace bad bits of firebox as long as you are operating.

dave