cold roll steel can be purchased in 1018, 1045 and 4140, and the 4140 alloy is perfect for pins and bushings, but the bushings made from it would need to be flame hardened before using... but the pins should NOT be hardened, as its better to wear the pins out than the bushings, because the pins are easier and cheaper to make and replace when they wear...
no... very weldable, and wont cause any brittleness.. preheat the end of pin just enough that its slightly hot to the touch, and then weld the tab on...So is 4140 QT SRA a suitable material? If i have to weld a tab on the end, will the pin become brittle?