There isn't enough data here. In general the strength is effected by- alloy, carbon, chrome, molybdenum etc. Then manufacturing, forging, rolling, drawing, etc. all tend to develop grain structure which helps strength. Then heat treating which properly done optimizes the material to its use. None of these are exclusive of the others so that a forged chrome-moly part is well within the realm of possibilities.
Bill
Are you talking about axle shafts for race cars,equipment,wagons?Are the chrome moly axle shafts tubes with welded ends,Solid machined?Heat treated?Are the stock forged ones stock replacements or a larger size than staock?Are they hollow?Gun drilled?Spline count?Flanged on outer end or slip on hubs?Many questions to be answered.