Forgings?
- Thread starter Fairlane500
- Start date
dumb person
Well-known member
i think forgings have parting lines too though.
Fairlane500
Senior Member
They just seem a little too clean for castings, they do have a line on them though. I don't want to heat and ruin the arm if its a casting, someone might need it one day...
I built the MIG welders for Snap On tool co and toured the plant several times. They had large hammer presses the height of a telephone pole. A white hot piece of metal is put in a bottom female die, the hammer is tripped and the top female die comes down on the hot metal shaping it into the dies. The hammer may be tripped 3 or 4 times until the upper die bottoms. Flash metal is extended out along the center of the part. If the metal used to start with is a controlled size the flash is minimal. The part is then put in a trimming die which shears most of the flash off. If the trimming die is close little or no grinding may be required depending on the parts use. There is also a finishing room with a number of tumblers and large coffin like tanks with various sized and shaped "stones" and liquid in which the parts are dumped. The tanks are spring mounted and a motorized shaker moves the tank and the abrasive action cleans the part removing small burrs. This process can almost polish some parts.The next step in production is a finishing coat if required then the quality control room where people inspect every part visually and with go, no go gauges. G.M.
You are correct sir!
Fairlane500
Senior Member
Thanks that was what I was looking for someone who has done this before, I would hate to waste such a nice piece. Thanks John
G.M. That's a very good description of the Drop forging process.
About the width of the flash line, when the two halves of the dies meet they must completely close, so a gutter is machined into the bottom die for the flash to flow into. At this stage the flash may only be 1/16th-1/8th thick. When the forging is placed in the Trimmer die it is still very hot, the trimmer die shears the flash away and mashes what's left of the flash into the forging to make it as smooth as possible, thereby eliminating the need for grinding. This also has the effect of making the flash line seem much thicker than it really is.
About the width of the flash line, when the two halves of the dies meet they must completely close, so a gutter is machined into the bottom die for the flash to flow into. At this stage the flash may only be 1/16th-1/8th thick. When the forging is placed in the Trimmer die it is still very hot, the trimmer die shears the flash away and mashes what's left of the flash into the forging to make it as smooth as possible, thereby eliminating the need for grinding. This also has the effect of making the flash line seem much thicker than it really is.
Fe26, It sounds like you were involved with the forging process, I was only exposed to it at my Snap On Tool Co visits. All I know it what I saw there 45 years ago. What we didn't discuss yet was the material used to form the part. I assume it is plain low carbon steel or a higher allow depending on the use of the part?? The forcing or squeezing the metal into a confined area with large forceful blows I think would make the grain structure smaller and the finished metal stronger?? It seems the forgings can be bent either cold or by heating with out damaging them, heat would probably be the preferred method except for slight alignment type bends.
At least a forging is not like cast materials that are prone to breaking G.M.
Mart
Well-known member
Here's another little angle to throw into the mix.
32 levers are long and somewhat hard to come by.
If I had a long lever like that I would look at reshaping it to the 32 shape. I would then look at lengthening the end of the shorter lever by welding a piece on and drilling a hole or holes further out.
Depends if you or a buddy could use a 32 length lever, I guess.
Mart.
32 levers are long and somewhat hard to come by.
If I had a long lever like that I would look at reshaping it to the 32 shape. I would then look at lengthening the end of the shorter lever by welding a piece on and drilling a hole or holes further out.
Depends if you or a buddy could use a 32 length lever, I guess.
Mart.
Fairlane500
Senior Member
Great Thanks!
Fairlane500
Senior Member
This is a 1947 Right Hand Drive truck lever I am told.
Yes GM I was an industrial blacksmith hence my moniker Fe26 which is the symbol and atomic number for iron. Drop forging steels are highly specialised alloys. As you mentioned the slugs are heated to almost white hot, at this temp. carbon is being burned away thereby reducing the strength of the steel so other alloys are added as well as a higher carbon content to counteract the loss. Also the steel has to flow well and fill the die so alloys are added to allow that to happen. Then after you've invested all this time and money in making the dies and forgings you don't want the forgings to have any flaws, so vanadium is added to purify the steel. Depending on the use of the forging other alloys can be added like chromium if you're making tools to give the tool a smooth shiney rust free appearance.
Forging not only compresses the grain structure but also aligns it. This is where the skill of the Blacksmith comes in. When the grain structure is aligned the steel becomes very very strong. Sometimes before a slug is put into the drop forger, the grain must be 'worked up' by forging under a Clear space hammer, and sometimes roughly shaped to get the slug into the first die. A die set might have three - six impressions, the slug is roughly shaped in the first impression, put into the second where a little more shaping or refining happens and so on until the final job is the trimmer die.
Another facet is the size of the hammers, as you observed they are bloody big, and you would be right in thinking the size of that machine is way past overkill for that little forging. But whats really going on is 'Energy = Heat' and a big hammer has a lot of energy.
As the hammer hits the forging it gets hotter with each blow, and that means you don't have to put it back into the furnace as you progress through the impressions.
Hey GM, I'll let you tell the guys about how the floor shakes, and the noise.
Will end up shortening to desired length as will run out of pedal travel before clutch disengages, but somewhere in the middle should work...
