Jura T

No. In theory it shouldn't be needed. Quenching is sometimes used for decreasing the grain size, instead of normalizing. However, quenching is always a bigger shock to the steel than normalizing...

I wanted to make a hammer, similar to the one Brian Brazeal has demonstrated making. I got the shape to my liking and normalized the hammer. As I had put quite a few hours into making it, I wanted to harden it as well as possible. So I heated it to non-magnetic and quenched in oil. It did not harden. I was using spring steel (~50CrV4), that has hardening temperature slightly higher than normal carbon steel. So next time I heated it a tad past non-magnetic. Still not good. One more heat, again slightly hoter than last time, but this time I only heated the two faces. Now the faces hardened alright. BUT, there was a crack on the other end! Any guesses whether the crack was caused by the multiple quenches or by the differential heating at the last stage? On the plus side, the grain looks ok.

The electrician came last weekend and we measured the currents. The plate on the motor says 5.5kW@380V, cos(phi)=0.86. The three phase voltage is 400V over here nowadays. So if I got it right then the max current would be I=P/(sqrt(3)*U*cos(phi))=5500W/(sqrt(3)*400V*0.86)=9.23A Here is what we measured: start: 10.1A idle (ram down): 5.3A light blows: 8.6A heavy hits: 9.7A --> sqrt(3)*400V*9.7A*0.86=5.78kW (*) We also measured the currents with somewhat more loose belts and the results were more or less the same. I think the tightness on the belts should be ok now. (*) As the voltage is higher the motor output is also probably higher. Can I simply calculate it like this 400V/380V*5.5kW=5.79kW?

The video is of such bad quality, that I'll see if I can take a better one.

I got a welding fume extractor for three bottles of cognac. I have had it for couple of weeks now and I really like it. Earlier, when welding or quenching in oil, I had to open the door to get all the fumes out. That method isn't too nice to use when it is -20C outside. :)

Here is one picture of the hammer. Sorry, no action pics. I did take a short video with my mobile phone, but it seems that one cannot upload any videos to the site...

Thanks, that's a good advice. I'll have an electrician coming to add a new switch to the hammer within next couple of weeks. I'll ask him to measure the amps at the same time.

Sam, I try to remember to take a couple of pictures next weekend.

I raised the motor so that the belts have now that one inch movement with moderate pushing force. The power of the blows is back to normal.:)

I have an old russian self contained hammer (similar to Beche and Anyang). Today when I started using it I noticed that it slowed down after couple of blows. It didn't stop completely, but went down to maybe half the normal speed under load. I haven't noticed the slowing down earlier. I guess them most logical explanation is that the belts have started to slip. I checked them and to me they seemed quite loose. Free distance for the belts between the pulleys is about 60 cm (24 inches). In the middle they move more or less freely about 3.5 cm (1.4 inches) sideways (from the center line). Tomorrow I'll put some spaces under the motor to get the belts tighter. How tight should they be so that they stop slipping, but wont put too much pressure on the bearings?

I really like to the leaf, so I had to give it a try myself.

Great to have you back here, Frosty!

Powell's is already on the google map that a colleague of mine did. The Technical Bookstore is a good hint, thanks. I wouldn't mind finding some books by Dona Z. Meilach and some other blacksmithing books.

Thanks for the info. Fort Vancouver sounds interesting.

Quick googling reveals that there is Portland in Australia as well, one in New Zeeland... I didn't realize that Portland has been so popular name for places. I'm going to Portland, Oregon, USA.

I'm having a work trip to Portland (USA) next weekend/next week. I'll have one day off, so is there anything interesting (blacksmithing related or not) to see/visit? One thing that I hope to find, that I haven't seen here in Finland, is a butcher's block brush with stiff wide bristles. Should I look for a hardware or a kitchen supplies shop to find one?

Thanks for the link. I went to the website. They talked about grain flow, but then at the same time show the same picture (http://www.scotforge.com/images/photo/graingrowth3.gif) as many other sites. In that picture there is no directional preference of the grains in the steel at the end of the process. That got me finding out what is actually meant by "grain flow". I found a book called "Steel forgings: design, production, selection, testing, and application". The was a two page preview on Google books, from which I found the following information: "Differences in tensile ductility, measured as elongation and reduction of area, are largely caused by the effects of nonmetallic inclusions in the steel. Increased numbers of inclusions will accentuate the ductility differences between the longitudinal and transverse directions. Alignment and elongation and spreading of inclusions parallel to the direction of hot working are the major sources of these directional property differences." I also found some slides where there is a picture of the flow lines caused by inclusions (http://www.utm.edu/departments/engin/lemaster/Machine Design/Lecture 02.pdf see slide 11/28). Furthermore, on this site, JobShop.com Technical Article - MAKING THE MOST OF FORGING BENEFITS: GRAIN FLOW BOOSTS PRODUCT PERFORMANCE, it says "From a metallurgical perspective, the degree of directionality or grain-flow sensitivity depends on the degree of recrystallization (diminishing the effects of grain flow in pure metals), and microstructural characteristics (inclusions, chemical banding, and undissolved phases), which in most structural alloys tend to promote directional sensitivity." So it seems that the expression "grain flow" is somewhat misleading. It is not the alignment of steel grains that produces the directional properties, but the alignment of inclusions. My initial, more or less theoretical approach, was severely limited in that sense, that I assumed that we had pure steel. So, as Jake noted, it is really nice that more experienced smiths bring in the understanding of steel. I still believe that for the steel part, we can remove the alignment of the grains by heat treatment (by my understanding the quotation from jobshop reassures that assumption). However, at the same time we cannot remove the flow of inclusions. I sticking to that (until someone, once again, proves me wrong ).

Use it for assembly like Hofi does: I Forge Iron - BP1015 How To Use A Magnet

Look also at this illustration: http://cashenblades.com/articles/lowdown_files/recrystal.jpg That seems to give the same picture of what is happening as a lot of other sources I have seen, ie after heating to austenite temperature the grains come equiaxial. As Grant noted the grains start growing from the boundaries/dislocations and thus the result could be that they are in chain like configuration. I can see that to some (small) extent in the recrystallisation picture in the Krauss's book. Then again the structure of the cold rolled iron isn't as "clean" as in Cashen's picture. The elongated grains tend to bee pointing to same direction, but there is still same variation in the direction and size. So, yes, I can believe that the grain configuration of a cold rolled steel can have some directional information after heating it once. Heat it twice and that should, IMHO, have gone. Now I have admit that all my information comes from books. I have not done any testing my self. If, you Grant and others, say that cold rolled steel has strong directional differences even after normalizing, then either the books are wrong or my interpretation of the info I have read is wrong. It could be that alloying elements change the situation. There can be, for example banding of alloys. Phil, if you cold fold a piece then there should still be the elongated structure of the grains. So I can easily believe that there are directional differencies.

Looks really robust. Congrats. Is there hole going through the frame for long forgings? How large motor does it need?

So you really like big hammers . The LG type hammer you have isn't the smallest one either.

To be precise, the the lattice structure of the crystal is cubic, not the grains themselves. If you mean that we cannot change the longitunal structure of the grains, then I disagree with you. In the book "Steels: heat treatment and processing principles" by George Krauss there is a nice pair of pictures (section Process and Recrystallization Annealing) that shows the longitunal grain structure of cold rolled iron. After annealing at 538C (1000F) the structure has recrystallized to equiaxed grains. (The recrystallization happens due to dislocations that cold rolling has intruduced.) I haven't found similar pair of pictures showing the result when going to austenite temperatures. However, Krauss's book and other sources as well, describe that the austenite grains start growing from the existing grain boundaries. The new austenite grains grow more or less equiaxially. Thus one normalizing cycle should destroy the longitunal grain structure.

Great to hear that Frosty is on steady recovery track. I didn't notice at first, but there seems to something behind the Bedpan Forge. I wonder how he that in there. :o

Japanese file making: