The price ratio is roughly 6 historically, it has lowered to as low as 4 only recently, and stainless steel has been largely used, since the '80's, instead of c

The price ratio is roughly 6 historically, it has lowered to as low as 4 only recently, and stainless steel has been largely used, since the '80's, instead of conventional rebar steel. But there is no stainless steel capable of having the same resistance/elasticity of cable steel. To give you some comparative data in EU the normal rebar since more than 40 years is usually grade 44 or 45 that means that it starts elongating (and eventually fail) around 4300-4500 Kg/cm2 and breaks over 5400 Kg/cm2 (still as a reference normally the calculation uses a max of 2600 Kg/cm2). Cable steel (again since more than 40 years), typically in 7 wire strands, is almost 4 times stronger, the same values are 16700 kg/cm2 and 18600 kg/cm2. Typically it is pre-stressed to 12500-13600 kg/cm2.