Chromium low alloy steels are characterized by which of the following statements?

• A. increased tensile strength, hardenability and corrosion resistance
• B. low carbon content promotes brittleness
• C. with <0.18% carbon can be welded without cracking - requires pre and post heat
• D. low strength and poor weldability

Answer: (C)

Weldability of chromium low alloy steels hinges on carbon content. When carbon is kept very low, below about 0.18%, the tendency to form hard, brittle martensite in the weld and heat‑affected zone drops, which reduces cracking risk during welding. That makes these steels easier to weld, especially with the use of preheating and post‑weld heat treatment to manage residual stresses in thicker sections. Chromium adds strength and some corrosion resistance, but the defining trait for welding is the very low carbon level. The other statements either overgeneralize about properties or contradict the known weldability behavior of low‑carbon chromium steels.