निम्नलिखित में से कौन सी प्रक्रिया सतह के सख्त होने (सर्फेस हार्डनिंग) का एक प्रकार नहीं है?

Which microstructure is typically obtained after normalizing low-carbon steel?

Match the heat treatment processes in Group A with their primary effect on mechanical properties in Group B: Group A (Heat Treatment) a. Annealing b. Nitriding c. Martempering d. Normalizing Group B (Primary Effect) A. Refines grain structure B. Improves hardness of the entire mass with minimal distortion C. Increases surface hardness significantly D. Improves ductility and relieves stress Select the correct sequence matching a, b, c, d: