Oxy-acetylene welding — temperature at the inner luminous cone of a neutral flame In gas welding practice, what is the approximate temperature at the tip of the inner luminous cone for a neutral oxy-acetylene flame?

Introduction / Context:
The oxy-acetylene neutral flame is the most commonly used flame for fusion welding of steels. Knowing the temperature at the inner luminous cone helps a welder judge heat input, travel speed, and suitability for base metals and filler rods.

Given Data / Assumptions:

• Neutral flame (balanced oxygen and acetylene).
• Temperature asked at the inner luminous cone tip, where maximum useful heat is concentrated.
• Standard torch and normal working conditions.

Concept / Approach:
A neutral oxy-acetylene flame has two distinct regions: an inner luminous cone (primary combustion) and an outer envelope (secondary combustion). The inner cone is the hottest and is used for welding. Typical peak temperatures for a neutral oxy-acetylene flame are around 3200° C at the inner cone, which is significantly higher than flames obtained from other gas combinations like oxy-hydrogen.

Step-by-Step Solution:
Identify flame type: neutral oxy-acetylene.Recall typical peak temperature near inner cone: approximately 3200° C.Compare options and select the closest accepted value.

Verification / Alternative check:
Reference values used in welding handbooks show oxy-acetylene neutral flame maximum temperatures in the 3100° C to 3200° C range; bench practice aligns with using the inner cone for efficient heat transfer.

Why Other Options Are Wrong:

• 1000° C and 1250° C: far too low for fusion welding of steels.
• 2100° C: closer to some air-fuel flames but below oxy-acetylene capabilities.

Common Pitfalls:
Confusing overall flame temperature with effective temperature at the cone; also mixing values for oxy-hydrogen and oxy-acetylene flames.

Final Answer:
3200° C