34557564 Posted February 10, 2012 Share Posted February 10, 2012 These tools both broke (chisel and punch) when I tried to use them. They were both forged from coil springs. Funny thing is, the grain patterns are so different! They were heat treated identically (quench tip in water, let it go to straw then quench tool). I think I'll order some 5160 round for tools. Would you heat treat them the way I described, or oil quench? Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 10, 2012 Share Posted February 10, 2012 You should have quenched in oil not water. You can see the quench crack in the steel on the one on the left. Also you did not draw the temper far enough you should have gone to purple or blue. The one on the right looks like it was quenched at too high a heat. Quote Link to comment Share on other sites More sharing options...
34557564 Posted February 10, 2012 Author Share Posted February 10, 2012 Interesting! So, can I stick with coil springs or should I buy some new stock? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 10, 2012 Share Posted February 10, 2012 Oil quench, don't forget to normalize and remember that "old time advice" was for old time steel alloys! Quote Link to comment Share on other sites More sharing options...
pkrankow Posted February 11, 2012 Share Posted February 11, 2012 It looks like they broke at the waterline. Were you stirring and dipping so there was no distinct waterline? Oil is more suitable for coil spring (usually). Were you using a means for temperature control? Magnet on copper wire, Tempil, or just by "eye"? Both look like they have a spiral crack running lengthwise. Clean the fire scale off before heat treat next time, and after tempering to make sure. If your next couple tools show a lengthwise spiral crack when finished and cleaned this spring is junk, but otherwise it is fine and the aggressive quench probably was the culprit. I would go ahead and make two new tools, they will turn out WAY better than these two did. Thomas has it right with normalizing, and Tim with oil quench. A quart of cooking oil (I use canola) is perfect for punches of this size. You can use quart paint can even. Phil Quote Link to comment Share on other sites More sharing options...
34557564 Posted February 11, 2012 Author Share Posted February 11, 2012 This evening I made a new hot chisel (same coil spring), and quenched it in warmed canola oil. We'll see what happens! Thanks for the tips! Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 11, 2012 Share Posted February 11, 2012 ATF fluid works very well as a quench. Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 11, 2012 Share Posted February 11, 2012 I agree with Tim. They were both under-tempered, and the chisel on the right was also overheated. (It may not have been during the heat-and-quench cycle; it could've happened during forging.) Like many other things in metallurgy, tempering is a function of temperature and time. Letting the colors run gives the hardened steel minimal time at temp. I prefer at least a couple one-hour cycles in the oven at the desired temperature. If you're going to try letting the colors run from an unquenched part of the tool, you might want to try tempering higher than you would in the oven. (In other words, if you're going to skimp on time, try a somewhat higher temp.) The solution to the grain size problem is normalizing. Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 11, 2012 Share Posted February 11, 2012 I agree with Tim. They were both under-tempered, and the chisel on the right was also overheated. (It may not have been during the heat-and-quench cycle; it could've happened during forging.) Like many other things in metallurgy, tempering is a function of temperature and time. Letting the colors run gives the hardened steel minimal time at temp. I prefer at least a couple one-hour cycles in the oven at the desired temperature. If you're going to try letting the colors run from an unquenched part of the tool, you might want to try tempering higher than you would in the oven. (In other words, if you're going to skimp on time, try a somewhat higher temp.) The solution to the grain size problem is normalizing. You know what you are talking about, but long heat treating cycles are not appropriate for a smith who is making a tool to put right into use. Shop conditions often dictate that a tool be forged heat treated and used right away. I often make punches in 10 or 15 min quench, temper and use. These tools are made from track springs "pandrol clips". I will often forge the tool take a normalize heat let it cool to 4-500 and take a hardening heat. I then temper to the desired hardness. I have tools that I have used for years made this way. What you are talking about is more appropriate for professional grade edge tools that are being made for resale. Obviously if you are willing to spend the time you will get better results. But is it worth it for a quickly made tool you may only use a few times or one that is going to be in contact with hot steel? Scrap steels are a wonderful resource I have made good use of them over the years. I am no expert on heat treating but I understand the basics and my tools rarely fail. This is the result of years experimentation, reading, and talking to other smiths. Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 11, 2012 Share Posted February 11, 2012 Sure, Tim, I understand that sometimes you need the tool right away. I admit that I may occasionally get a little carried away , but I did try to compensate for that by offering the quicker and dirtier alternative: if he wants to temper by letting the colors run, he should aim for a higher temp than he'd use if he were oven tempering. In other words, I agree that the purple or blue that you suggested is probably about right. (Even if the tool turns out slightly overtempered that way, a little too soft and tough is usually better than a little too hard and brittle, when it comes to smithing tools.) I do think at least one normalizing heat before the quench is almost always a good idea, though. It only takes a couple minutes on most hand-held tools. Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 11, 2012 Share Posted February 11, 2012 Yes normalizing is a key step and should not be skipped. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted February 11, 2012 Share Posted February 11, 2012 Since the debate of the value of heat treat has started, with hot chisels and hot punches the value of going through a specific heat treat in the first place is limited as the temper on the tool will be drawn further in proper use, in fact in proper us the temper may be "fully drawn" (another reason it is safe to temper to dark blue on a hot chisel) The value of the heat treat exercise to a new smith is probably worth more than the final improvement on the tool as the difference in tool hardness (when the tool is cold) between normalized and fully draw temper is fairly minimal. Cold work tools should be fully heat treat as there is a definite significant improvement in the steel hardness and durability. Phil Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 11, 2012 Share Posted February 11, 2012 Good point. Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted February 11, 2012 Share Posted February 11, 2012 Many coil and leaf springs are made of 5160, but some of them aren't. A guy can experiment with it, especially if he knows a little something beforehand. 5160, a spring steel, is referred to loosely as "carbon-chromium" steel and sometimes called a "silicon-manganese" steel. Chromium, silicon, and manganese are the main alloying ingredients. For forging, you can take it up to 2100-2200F (bright lemon or yellow heat). I usually stop forging at a low cherry red and re-heat, although I don't have specs on this. Normalizing is done at 1600-1700F (bright red, above cherry range and below orange). Air cool on a non-reactive surface. The hardening temp is 1500-1550F (bright cherry red) in oil. In industry, they temper anywhere from 800F to 1300F. For our chisel use, we usually go to 545F to 560F purple to full blue surface temper color on abraded steel. I have a "Forging Industry Handbook" from 1970, and they list as spring steels: 1050; 4161;5155; 5160; 6150; 9260; and 51-B-60. And that was 1970! Take care. References: Forging Industry Handbook Heat Treatment and Properties of Iron and Steel, US Gov't monograph 88, 1966 Steel Aluminum Stock List; Jorgensen Steel Metals for Engineering Craftsmen, London 1964 [temperature chart] Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 11, 2012 Share Posted February 11, 2012 Since the debate of the value of heat treat has started, with hot chisels and hot punches the value of going through a specific heat treat in the first place is limited as the temper on the tool will be drawn further in proper use, in fact in proper us the temper may be "fully drawn" (another reason it is safe to temper to dark blue on a hot chisel) The value of the heat treat exercise to a new smith is probably worth more than the final improvement on the tool as the difference in tool hardness (when the tool is cold) between normalized and fully draw temper is fairly minimal. Cold work tools should be fully heat treat as there is a definite significant improvement in the steel hardness and durability. Phil So Phil you are saying I should take the time to do a several hour heat treat on a cold chisel that I made to get at a tight area on a custom job. The tool will go in a old soup can and probably not used for the next year or 2. Practical experience does not bear out what you say. I have made many a tool by my method above. Some I have used hundreds of times. This would be virtually impossible to do by a guy working out of an old rivet forge in his back yard on week ends. Smiths heat treated this way for centuries and made amazing tools and weapons, somehow we survived. We are not going to send the chisel into space or have it last 300,000 miles Quote Link to comment Share on other sites More sharing options...
pkrankow Posted February 11, 2012 Share Posted February 11, 2012 Tim, I consider a "backyard" heat treat a full heat treat, even if it only takes 15 minutes (or less). Similarly a full hardening and oven tempering process is another full heat treat process. A full heat treat (apparently in my opinion) is simply following a schedule of controlled heating and cooling operations to achieve desired proprieties. Which set of heating and cooling operations you choose is up to you, but it should be based on the material you are using and what it will respond favorably to. I also say use your best judgement. I doubt you would deliberately choose a material that does not respond to your process. I also doubt you would choose a material that requires a lengthy difficult process for a rarely used tool. Phil "Typical" backyard process normalize heat to non-magnetic end quench or fully quench in suitable medium abrade metal to bright along lenght and end allow residual heat to draw temper, or add heat needed to run colors quench to cool Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 11, 2012 Share Posted February 11, 2012 "Full heat treat" is a very general term when we are tiring to be specific it has little value in clarifying the issue. Quote Link to comment Share on other sites More sharing options...
FordPrefect Posted February 12, 2012 Share Posted February 12, 2012 The way I see it as a beginner blacksmith, use the metal you are most comfortable in using for what ever you want to make, perhaps staying with one type of metal till you master the basic forging techniques and HT techniques for that particular metal, this is my approach to learning. Adding different metal types till you exhaust all basic metal types (1018, 1045, etc.) will add to your knowledge base, this will be used in the future to work unknown metals or junk yard metals, if so desired. This is what works for me, otherwise there is always trial and error, hands on, with figuring out unknown metal properties, which is also a desired element and which should be a part of the learning curve. Having the ability to ask a full time working blacksmith a question on a on any step in a forging process is priceless, thank God for IFI, for those of us working hobbyist that do not have time to take classes, this is a time and money saviour. Thank you guys, and you know who you are since you answered so many question, and at times repeated questions, I am sorry for repeated questions but some of us learn by repeating over and over till it sinks in (I think it has something to do with age). Thank you IFI. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 13, 2012 Share Posted February 13, 2012 So, since blacksmiths using alloys available back in the day, did things one way. You using modern alloys should be able to do the same? Do you clap a leech on when you hurt yourself too? They did that for centuries too! You need to use the appropriate heat treat for the alloy you are using. Back in the 19th century smiths commonly quenched items made from real wrought iron from red hot to cold. Doing so with A36 can make you a very unhappy smiter indeed! Some alloys you can get away with quick and dirty heat treats; some alloys you will have wasted your time doing so. Learning which ones are which is part of the process of becoming a smith! Saying that because they did it with alloy A I can do it with Alloy B does NOT hold. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted February 13, 2012 Share Posted February 13, 2012 If people would take the time to learn about the alloys before using them, many problems would be avoided. For example, quenching a chrome bearing steel in water and wondering why it cracked, rather than read what is already posted here easy to find first? Also its is explained in the heat treat sticky's that for unknown steels try air first, then oil then water. Five minutes of reading vs a ruined tool. your call. A smart man learns from his mistakes, a wise man learns from others mistakes. Quote Link to comment Share on other sites More sharing options...
Blacksmith Johnny Posted February 14, 2012 Share Posted February 14, 2012 Real good point Steve Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted February 15, 2012 Share Posted February 15, 2012 " the steel will be further drawn in proper use" I do not agree at all. We taught shoeng students and so did the folks before me to make punches to use in hot metal for abouit forty years using junkyard coil springs. None of them change the heat tret on these tools by properly useing them. They were taught to punch the hot steel a couple hits and then cool the tool then resume the process. Those that chose to maintain contact with the hot steel until the tip of the punch was heated learned that the punch needed to be redone the same as the first heat treat to keep it usable. Keep in mind that as said above heat treat is about time and temperature. and simply put the end of a punch used properly will not attain the heat necessary to change its hardness unless the time at temp is achieved. Even if we say these things in here inadvertantly they may again confuse the new folks that read each and every line and try and sort out a method that will work for them. Quote Link to comment Share on other sites More sharing options...
dimenickel Posted February 15, 2012 Share Posted February 15, 2012 myself ...i'd stay away from temper colors.. its not accurate... temper in an oven and hold for 2 hrs... cool and repeat -as you don't really know what alloy your dealing with - one looked like the grain was abit coarse good luck Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 15, 2012 Share Posted February 15, 2012 I personally have a theory that some blacksmith heat treats may work OK because they're not achieving full hardness to start with, and/or because they're using inherently tough steels that won't get terribly hard in the first place. 1045 isn't going to harden much in most oils, for example, and even at full hardness it'll still be pretty tough, especially in thicker sections. But it's just a theory. I don't mean to offend anyone. If your heat treat gives you the results you want, that's ultimately all that counts. Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted February 16, 2012 Share Posted February 16, 2012 I personally have a theory that some blacksmith heat treats may work OK because they're not achieving full hardness to start with, and/or because they're using inherently tough steels that won't get terribly hard in the first place. 1045 isn't going to harden much in most oils, for example, and even at full hardness it'll still be pretty tough, especially in thicker sections. But it's just a theory. I don't mean to offend anyone. If your heat treat gives you the results you want, that's ultimately all that counts. Blacksmiths invented heat-treating some are good at it and some are not that good. About 2700 years later scientists and engineers began to study metallurgy. By doing repetitive testing they were able to learn the optimal conditions to harden and temper various types of steels. Think about all of the things that were made with hand forged tools up until the early 20th century when they finally got a handle on what was going on. Is it all that important that you get that extra 10% of performance out of a cold chisel or hammer head in the context of a blacksmith shop. Quote Link to comment Share on other sites More sharing options...
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