Technically there is a difference between stressproof and just plain 1144. If you are going to be using it for axles, drivelines, transmission shafting etc, be sure to specify stressproof. It is actually a commercial trademark name, but all mills have their version of "stressproof", all based on the 1144 base material and then thermally treated. It is an excellent material, all the way around. It has higher machineability, stiffness, tensile yield, and ultimate tensile than 1045 and 4140 in their NORMAL states. I have found it to be weldable in most situations. Check with a good metallurgist to prevent weld related problems for your specific application.