Welding Skills, Entry-Level 01 by Welding

Author:Welding
Language: eng
Format: epub, pdf

178

CHAPTER 6

A W S S E N S E E G 2 . 0

Key Indicators Addressed in this Chapter:

Module 8: Thermal Cutting Processes

Unit 1: Manual Oxyfuel Gas Cutting (OFC) Key Indicators Key Indicator 1: Performs safety inspections of manual OFC

equipment and accessories

Key Indicator 2: Makes minor external repairs to manual OFC

equipment and accessories

Key Indicator 3: Sets up for manual OFC operations on carbon steel Key Indicator 4: Operates manual OFC equipment on carbon steel Key Indicator 5: Performs manual OFC straight, square edge, cutting operations, in all positions, on limited thickness

range of carbon steel

Key Indicator 6: performs manual OFC shape, square edge, cutting operations in all positions, on limited thickness

range of carbon steel

Key Indicator 7: Performs manual OFC straight, bevel edge, cutting operations, in all positions, on limited thickness

range of carbon steel

Key Indicator 8: Performs manual OFC scarfing and gouging operations to remove base and weld metal, in 1G

and 2G positions, on carbon steel

Unit 2: Mechanized Oxyfuel Gas Cutting (OFC)

Key Indicator 1: Performs safety inspections of mechanized OFC

equipment and accessories

Key Indicator 2: Makes minor external repairs to mechanized OFC

equipment and accessories

Key Indicator 3: Sets up for mechanized OFC operations on carbon steel

Key Indicator 4: Operates mechanized OFC equipment on carbon steel

Key Indicator 5: Performs mechanized OFC straight, square edge, cutting operations, in 1G and 2G positions, on

limited thickness range of carbon steel

Key Indicator 6: Performs mechanized OFC straight, bevel edge, cutting operations, in 1G and 2G positions, on limited

thickness of carbon steel

Module 9: Welding Inspection and Testing Principles

Key Indicator 1: Examines cut surfaces and edges of prepared base metal parts

INTRODUCTION

Oxyfuel gas cutting (OFC) describes a group of oxygen cutting processes that use an oxyfuel gas flame to heat metal to its kindling temperature before a high-pressure stream of oxygen is directed onto the metal to cut it. The kindling temperature of a material is the temperature at which rapid oxidation (combustion) can begin. The kindling temperature of steel in pure oxygen is 1600°F to 1800°F

(870°C to 900°C). The OFC processes are identified by the type of fuel gas used

Flame Cutting

179

Table 6.1 Fuel Gases Used for Flame Cutting

Fuel Gas

Flame (Fahrenheit)

Temperature* (Celsius)

Acetylene

5589°

3087°

MAPP®

5301°

2927°

Natural gas

4600°

2538°

Propane

4579°

2526°

Propylene

5193°

2867°

Hydrogen

4820°

2660°

*Approximate neutral oxyfuel flame temperature.

with oxygen to produce the preheat flame. Oxyfuel gas cutting is most commonly performed with oxyacetylene (OFC-A). Table 6.1 lists a number of fuel gases used for OFC. MPS (MAPP®) gas is increasingly being used today for cutting and rivals acetylene’s popularity in some areas of the United States.

More welders use the oxyfuel cutting torch than any other welding process.

The cutting torch is used by workers in virtually all areas, including manufacturing, maintenance, automotive repair, railroad work, farming, and more. Unfortunately, it is one of the most misused processes. Most workers know how to light the torch and make a cut, but their cuts are of very poor quality. Often, in addition to making bad cuts, they use unsafe torch techniques. A good oxyfuel cut should be straight and square and should require little or no postcut cleanup. Excessive postcut cleanup results in extra cost, which is an expense that cannot be justified.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.