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HAZ High in One Area
- Thread starter MrGezus
- Start date
EdStainless
Materials
A fluctuation in welding conditions, speed, feed, or power.
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Plymouth Tube
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Plymouth Tube
Also preheat (minimum interpass temp.)
Also were the hardness measurements made across the HAZ or at the 6:00, 9:00 and 12:00 locations about the circumference? There will always be variation across the width of the HAZ. The variation shown is not abnormal when taken at the previously stated circumferential locations.
Also were the hardness measurements made across the HAZ or at the 6:00, 9:00 and 12:00 locations about the circumference? There will always be variation across the width of the HAZ. The variation shown is not abnormal when taken at the previously stated circumferential locations.
Guest102023
Materials
Do you mean the variance between the three hardness numbers? If these are distictly different locations then they should not be reported as a group.
You should do 3-5 tests at each location of interest and report the mean of each.
The range of numbers you report is quite normal for HAZ variation. The end point of your weld will be considerably hotter once the arc has travelled one circumference. Having said all that, apparent fluctuation in HAZ hardness readings is also very much down to variation by the technician in locating the hardest sub-zone immediately adjacent to the fusion line.
In general, HAZ hardness in carbon and alloy steels will decrease if preheat and interpass temperature increase, all other parameters being equal.
In general, HAZ hardness in carbon and alloy steels will decrease if heat input increases, all other parameters being equal.
Increased travel speed will decrease the heat input, all other parameters being equal.
It sounds to me like you have put the cart of pretty appearance ahead of the horse of mechanical properties.
Or perhaps distortion is your issue; with GTAW you have chosen just about the most severe process in that respect. Playing with parameters won't change it that much.
.
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
You should do 3-5 tests at each location of interest and report the mean of each.
The range of numbers you report is quite normal for HAZ variation. The end point of your weld will be considerably hotter once the arc has travelled one circumference. Having said all that, apparent fluctuation in HAZ hardness readings is also very much down to variation by the technician in locating the hardest sub-zone immediately adjacent to the fusion line.
In general, HAZ hardness in carbon and alloy steels will decrease if preheat and interpass temperature increase, all other parameters being equal.
In general, HAZ hardness in carbon and alloy steels will decrease if heat input increases, all other parameters being equal.
Increased travel speed will decrease the heat input, all other parameters being equal.
It sounds to me like you have put the cart of pretty appearance ahead of the horse of mechanical properties.
Or perhaps distortion is your issue; with GTAW you have chosen just about the most severe process in that respect. Playing with parameters won't change it that much.
.
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
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