#### What is in this article?:

- Pre-Calculating Wire-Feed Speed, Travel Speed, and Voltage
- Formula, Sample Calculations

*Determining how fast to travel for a particular size weld bead can be an iterative, time-consuming process*

- Deposition rate
- Weld rate
- Travel speed
- Wire-feed speed

## Formula, Sample Calculations

### Deposition rate calculation

Deposition rate (lb./hr) = 13.1×(Wire diameter)^{2}×(Wire-feed speed)×(Efficiency)

- Wire diameter in inches (in.)
- Wire-feed speed in inches per minute (IPM)
- Efficiency (1.0 for solid wire, 0.85 for cored wire)
- This calculation is for steel only

*E.g.:* Wire diameter = 0.045 in. (1.2 mm) solid wire, WFS = 300 IPM.

Deposition rate = 13.1×(0.045)^{2} ×(300)×(1.0) = 7.96 lb./hr

**Calculating travel speed with deposition rate** — Knowing the deposition rate, we can calculate the travel speed in inches per minute (IPM) for a particular weld. Let's say we want to make a 3/8-in. steel fillet weld (assume 10% reinforcement or 0.4125 in. leg) using 0.045-in. solid wire at 300 IPM, the weight of weld metal per foot can be calculated by multiplying the density of steel (0.283 lb./in^{3}) by the volume of weld metal per foot as follows:

### Weld weight per foot calculation

Vol. of weld metal/ft=1/2×b×h×12 in.=1/2×0.4125 in.×0.4125 in.×12 in.=1.02 in^{3}.

Weight of weld metal/ft of 3/8 in. fillet weld=(0.283 lb./in^{3})×(1.02 in^{3})=0.2887 lb./ft.

From the calculation below, we see that the travel speed for a one-pass, 3/8-in. fillet weld would be 5.52 IPM, 11.03 IPM for a two-pass fillet weld, or 16.55 IPM for a three-pass weld.

### Travel speed calculation

Travel speed = (deposition rate)×(# of passes)/5×(weight of weld metal per foot {lb./ft}) = (7.96)×(1)/5 × (0.2887) = 5.52 IPM

**Calculating wire-feed speed with deposition rate** — Let's assume a requirement to make fillet welds at a rate of 12 lb./hr using 0.045 in. welding wire. We can calculate the WFS using the formulas below and Weight of Weld Wire per foot in Table 1.

### Wire-feed speed calculation

Wire-feed Speed = (deposition rate)/5×(weight of wire per foot {lb./ft}) = (12)/5×(0.0054) = 444.4 IPM

Wire Diam., in. | Weight of Wire (lb./ft) | Wire Diam., in. | Weight of Wire (lb./ft) |
---|---|---|---|

0.035 | 0.0033 | 3/32 | 0.023 |

0.040 | 0.0043 | 1/8 | 0.042 |

0.045 | 0.0054 | 5/32 | 0.065 |

0.052 | 0.0072 | 3/16 | 0.094 |

1/16 | 0.01 | 7/32 | 0.128 |

5/64 | 0.016 |

Of course, the travel speed for a one-pass, 3/8 in. fillet weld at 12 lb./hr deposition rate would be 8.31 IPM as calculated below.

Travel Speed = (deposition rate)×(# of passes)/5×(weight of weld metal {lb./ft}) = (12)×(1)/5×(0.2887) = 8.31 IPM

**Making it easier** — The Bartonian Conversion Factor (Table 2) makes things a bit easier for fillet welds. The example below uses the conversion factor to calculate travel speed at 5.57 IPM for that same 3/8 in. fillet weld using a 0.045 in. solid wire.

Travel Speed = 7.96×0.7 = 5.57 IPM (.2887)

Bartonian Conversion Factor (* assumes 10% reinforcement) | ||
---|---|---|

Leg Size, in. | Weight of weld metal per foot* | B* |

3/16 | .072 | 2.7 |

1/4 | .129 | 1.5 |

5/16 | .201 | 1 |

3/8 | .289 | 0.7 |

Travel Speed = Deposition Rate × B |

Weight of weld metal per foot can be calculated for any joint type by calculating the volume and multiplying by the density of the weld metal (eg. 0.283 lb./in^{3} for steel). However, the values shown in Table 3 through Table 6 eliminate the need to do the calculation. These values are taken from Table 12-1 in *The Procedure Handbook of Arc Welding* by the Lincoln Electric Co., and show the Weight of Weld Metal per Foot for several common joint types welded with steel.

The following sample calculations use Tables 3 through 6.

Plate Size, in. | Weight of Weld Metal (lb./ft) (20% reinforcement for each gap size below) | |||||
---|---|---|---|---|---|---|

1/16 | 1/8 | 3/16 | 1/4 | 3/8 | 1/2 | |

1/8 | 0.027 | 0.053 | 0.080 | 0.106 | 0.159 | 0.213 |

3/16 | 0.040 | 0.080 | 0.120 | 0.1559 | 0.239 | 0.319 |

1/4 | 0.053 | 0.106 | 0.159 | 0.213 | 0.319 | 0.425 |

5/16 | 0.066 | 0.133 | 0.199 | 0.266 | 0.398 | 0.531 |

3/8 | 0.080 | 0.159 | 0.239 | 0.319 | 0.478 | 0.638 |

7/16 | 0.093 | 0.186 | 0.279 | 0.372 | 0.558 | 0.744 |

1/2 | 0.106 | 0.213 | 0.319 | 0.425 | 0.638 | 0.850 |

3/4 | 0.159 | 0.319 | 0.478 | 0.638 | 0.969 | 1.28 |

1 | 0.213 | 0.425 | 0.638 | 0.850 | 1.28 | 1.70 |

1 1/2 | 0.319 | 0.638 | 0.956 | 1.28 | 1.91 | 2.55 |

2 | 0.425 | 0.850 | 1.28 | 1.7 | 2.55 | 3.40 |

Plate Size, in. | Weight of Weld Metal (lb./ft) (leg size is 10% oversized) | ||
---|---|---|---|

Flat weld | Convex weld | Concave weld | |

1/8 | 0.032 | 0.041 | 0.036 |

3/16 | 0.072 | 0.093 | 0.081 |

1/4 | 0.129 | 0.165 | 0.145 |

5/16 | 0.201 | 0.258 | 0.226 |

3/8 | 0.289 | 0.371 | 0.325 |

7/16 | 0.394 | 0.505 | 0.443 |

1/2 | 0.514 | 0.6595 | 0.578 |

3/4 | 1.16 | 1.48 | 1.30 |

1 | 2.06 | 2.64 | 2.31 |

Plate Size, in. | Weight of Weld Metal (lb./ft) (Vee-groove included angle) | ||||||||
---|---|---|---|---|---|---|---|---|---|

14° | 20° | 30° | 45° | 60° | 70° | 75° | 80° | 90° | |

1/8 | 0.0065 | 0.009 | 0.014 | 0.022 | 0.031 | 0.037 | 0.041 | 0.045 | 0.053 |

3/16 | 0.015 | 0.021 | 0.032 | 0.049 | 0.069 | 0.084 | 0.092 | 0.100 | 0.119 |

1/4 | 0.026 | 0.037 | 0.057 | 0.088 | 0.123 | 0.149 | 0.163 | 0.178 | 0.212 |

5/16 | 0.041 | 0.058 | 0.089 | 0.137 | 0.191 | 0.232 | 0.254 | 0.278 | 0.332 |

3/8 | 0.059 | 0.084 | 0.128 | 0.198 | 0.276 | 0.334 | 0.366 | 0.401 | 0.478 |

7/16 | 0.080 | 0.115 | 0.174 | 0.269 | 0.375 | 0.455 | 0.499 | 0.545 | 0.650 |

1/2 | 0.104 | 0.150 | 0.227 | 0.352 | 0.490 | 0.594 | 0.651 | 0.712 | 0.849 |

3/4 | 0.235 | 0.337 | 0.512 | 0.791 | 1.103 | 1.338 | 1.466 | 1.603 | 1.910 |

1 | 0.417 | 0.599 | 0.910 | 1.407 | 1.961 | 2.378 | 2.606 | 2.850 | 3.396 |

1 1/2 | 0.938 | 1.347 | 2.047 | 3.165 | 4.412 | 5.350 | 5.863 | 6.412 | 7.641 |

2 | 1.668 | 2.395 | 3.640 | 5.627 | 7.843 | 9.512 | 10.423 | 11.398 | 13.584 |

Cap Width, in. | Weight of Weld Metal (lb./ft) (cap reinforcement height) | |||
---|---|---|---|---|

1/16 in. | 1/8 in. | 3/16 in. | 1/4 in. | |

3/8 | 0.027 | 0.053 | 0.080 | 0.106 |

1/2 | 0.040 | 0.080 | 0.120 | 0.1559 |

3/4 | 0.053 | 0.106 | 0.159 | 0.213 |

1 | 0.066 | 0.133 | 0.199 | 0.266 |

1 1/4 | 0.080 | 0.159 | 0.239 | 0.319 |

1 1/2 | 0.093 | 0.186 | 0.279 | 0.372 |

1 3/4 | 0.106 | 0.213 | 0.319 | 0.425 |

2 | 0.159 | 0.319 | 0.478 | 0.638 |

**Sample Calculation No.1 —** 1/2-in. plate Vee groove weld with 90° included angle and 1/8 in. reinforcement using 0.052 in. solid wire, 90%Ar/10%CO_{2} shielding gas. Manufacturer recommends WFS at 325 IPM and 30 volts.

Deposition Rate (lb./hr) = 13.1×(0.052)^{2}×(325)×(1.0) = 11.51 lb./hr

Travel Speed for fill and cap passes = (11.51)×(6)/5×(0.849 + 0.199) = 13.18 IPM

**Sample Calculation No.2 —** 3/8 in. plate square butt weld into a backing, with a 3/16 in. gap and 1/8 in. reinforcement using 1/16 in. cored wire, 75%Ar/25%CO_{2} shielding gas. Our process runs great with WFS at 285 IPM and 26 volts.

Deposition rate (lb./hr) = 13.1×(1/16 in.)^{2} × (285)×(.85) = 12.39 lb./hr

Travel speed for fill and cap passes = (12.39)×(1)/5×(0.239 + 0.053) = 8.49 IPM

**Sample Calculation No.3 —** What should my wire-feed speed be if I want to make a fat, 1/4 in. fillet weld at 20 IPM travel speed using 0.045 in. solid wire and 90%Ar/10%CO_{2} shielding gas?

Re-arranging the Travel Speed calculation above to solve for Deposition Rate we get:

Deposition rate = 5×Travel speed×(Weight of weld metal {lb./ft})/(# of passes)

Depostion rate = 5×20 IPM×(0.165)/1 = 16.5 lb./hr

Re-arranging the Deposition Rate calculation above to solve for Wire-feed Speed we get:

Wire-feed speed = Deposition rate/13.1×(Wire diameter)^{2}×(Efficiency) = 16.5/13.1 ×(.045 in.)^{2}×(1) = 622 IPM

**Summary —** Using math and these simple formulas can reduce your weld-development time, and improve your pre-WPS documentation. These calculations will get you close, but some tweaking may have to be done to achieve your desired weld. Having a good starting point for welding procedure development will decrease time and guesswork on the shop floor.

**Kevin Beardsley** *of Lincoln Electric is a registered Professional Engineer with 21 years of manufacturing experience. *