I want to make a nice 3 pound rounding hammer. I can't seem to find any 4150 steel anywhere. Could I use an equal size of mild steel, and weld on an piece of S7 flattened out? I don't know if this will work. I also don't know about forge welding it, as it being a big piece of steel, and having no power hammer/press

Maybe look for some 4140 or 1045. I know there's places all over the states that sell hammer size stock of that stuff 

Well I had a friend who used to work in a vehicle axle plant and he once provided me this info:

the industry standard for axle steel was 1045H below 1 3/8" stock and 1541H for axles above that size, for trucks. This was reported to have been the material in the US for at least the previous 20 years. The H is a modified version of the steels. These modified steels are much more prone to quench cracking than plain 1045/1050, and  would suggest quenching in oil. These steels are also prone to grain growth if held at forging temp for very long without working the steel. They also had a 45 minute time limit from quench to temper.   They did use 4140 for some of the very large axles used in off road equipment like big front end loaders. 

He also said they made some hammers from them successfully.  Got any trucks in Nebraska?

I'll try looking for some 1045 online, I wasn't completely honest I did find some 4140 online but a 1-1/2 by a foot was $70. I do have a friend whose dad is a mechanic, try to ask around there. Thanks for the help, my main problem is my age. Not out of high school, so I'm broke. so I'm trying to find ways to stay in a budget.

 

40 minutes ago, Isaac said:

I'll try looking for some 1045 online, I wasn't completely honest I did find some 4140 online but a 1-1/2 by a foot was $70. I do have a friend whose dad is a mechanic, try to ask around there. Thanks for the help, my main problem is my age. Not out of high school, so I'm broke. so I'm trying to find ways to stay in a budget.

 

I understand that budget thing. I'm 39 and am staying in a budget as well. Thanks for the question as I was wondering the same thing

What Thomas said: get thee to a place that sells and services heavy trucks and Ag equipment. I know that Nebraska has big green tractors galore. Ask for bent/replaced shafts, axles and track pins.

I use hydraulic hammer bits, old shafting, and really big coil springs. Call some machine shops that build conveyor if you come up short on axel steel. The shafting we use is either heat treated 1045, or 4140. You need some pretty small peices ( under 6 inches) and they may help you out. Caterpillar track pins can be found in a lot of different sizes, some are really good for hammers. Another route is hydraulic cylinder rod. Some is chrome plated (if you get plated material, grind the plating off before forging) I used to get 4150 from naval ordinance through the vo tech school. Both are gone now...