i think A36 is steel with 36 ksi yied strength material
where as A36M is tha same where M stands for Metric.
please make it sure with others also.
A36 is a standard specification for carbon structural steel while A36M is the metric version of the same specification. The "M" in A36M denotes the metric unit system used for measurements. Both standards are essentially the same in terms of mechanical properties, chemical composition, and performance.