It is forbidden to use slimming steel bars now. Is cold-rolled ribbed steel bar a slimming steel bar? Is it better to use cold-rolled ribbed steel bars for cast-in-place slabs than first-class steel bars? Yes, the elongation of cold-rolled ribbed steel bars is very small. 02 specification and 10 specification have legal technical standards, which are used in many projects. The design site representative with registered structural engineer has the right to agree to use it as a substitute for plate reinforcement, but its design strength is limited to 360Mpa. Regular manufacturers do not belong to "slimming" steel bars. Cold-rolled ribbed steel bar for cast-in-place slab is not cost-effective due to the design strength limitation. It can't be used on low-grade concrete slabs.