AWS D1.1 SMAW Welding Certification Procedure Specifications
The AWS SMAW 4G welding certification procedure
specifications are almost identical to the AWS SMAW 3G welding
certification procedure specifications. This certification is very
similar to the 3G welding certification with a few exceptions. The first
main difference is that the AWS D1.1 4G welding certification certifies
you to do fillet welds in the 1F, 2F, 4F, positions, and groove welds
in the 1G, 2G, 4G, positions, but it does not certify you to weld in the
3F and 3G positions. By taking the 3G and 4G welding certifications
together, it certifies you to weld plate in all positions, and to do
fillet welds on pipe with a minimum diameter of 24 inches. When taking
these certifications together it also put them into a single procedure.
The other main difference is more customary then a procedure
specification that involves horizontal and overhead welding. When doing
horizontal and overhead welds they are typically done in stringer beads
verses flat and vertical welds using weave welds.
The 4G welding certification also comes in two thick nesses. The
first is the 3/8 inch limited thickness procedure. This is the one I am
taking. The second is the 1 inch thick plate and it the unlimited
thickness procedure. The limited thickness procedure certifies a welder
to steel between 1/8 to 3/4 of an inch thick steel. |
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The 4G welding certification also has the same expiration time
period. That is if you do not weld using shielded metal arc welding in
the overhead position it will expire worthless in 6 months or a 180
days. The welding certifications must be kept up to date with either an
employer signing the welding log in the back or simple take a refresher
course at a welding school and have them sign off on the procedure.
Welding Certification Procedure Specifications
- Welding Process. SMAW
- Joint Type. Butt
- Backing. Yes
- Backing Material. ASTM A36
- Root Opening. 1/4 to 5/16
- Grove Angel. 45 degrees
- Back Gouge. No
- Base Metal. ASTM A36
- Type or Grade. Steel
- Thickness. Groove. (in) .375
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- Filler Metals AWS Specification. A5.1
- Filler Metals AWS Classification. E7018
- Electrode Diameter. 1/8
- Amps. 90 to 140
- Electrode Characteristics Current. DCEP
- Shielding Electrode Flux (class). 4
- Stringer or Weave. Either
- Multi-Pass or Single Pass (per side). Multiple
- Interpass Cleaning. Mechanical or Wire Brush
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SMAW Welding Machine Set-Up
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The 4G procedure just like the 3G procedure states that the SMAW
welding machine needs to be set within the range of 90 to 140 amps. I
used the same Miller Dialarc 250 welding machine, setting it at a 116
amps like my 3G welding certification. When setting up my machine on a
practice bevel I found this setting to be just right. On the root and
fill pass I was able to do a weave and on the cap I did stringer welds.
As for my stringer welds I needed the machine to run hot enough for the
rod to be literally pushed into the metal without sticking. When I
weld overhead with a stick welder I typically just start the arc and
then shove the rod into the joint. I let the rod burn on its own rate
without any manipulation. Literally I do not move my hand and just lean
on the rod letting it do all of the welding. This technique works well
but requires the machine setting to be hot enough that the electrode has
no chance of sticking. Just playing around with the settings I got the
1/8 E7018 electrode to weld at a 140 amps in the overhead position and
put down a nice weld. The down side of this is if your electrode angle
is off just a bit you will get arc blow. I am mentioning this because
many new welders who try to weld overhead assume that you want the
amperage to be on a lower setting. The reality of overhead welding is
that the hotter the welding machine settings are, the easer to weld. Its
more psychological factor |
Preparation of the SMAW 4G Test Coupons
Unlike the 3G welding certification were I took a lot of pictures. I
did get caught up in the moment of taking the 4G welding certification
and forgot to take many key pictures. Unfortunately this is the real
test and there are no retakes while doing it!
The preparation of the 4G test coupons is the same as the 3G
procedure. These are the AWS D1.1 notes for the 4G SMAW procedure with
pictures:
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Here are the test coupons and this is how I received them. |
I grinded all of the mill scale off of the front of the bevel a
minimum of 1 inch back and also did the same for the back of the bevel.
. Then I grinded the bevel to get rid of all oxidation. That was
followed by rechecking of the bevel angle. Again each bevel was exactly
22.5 degrees and it was inspected. Here is why it was done in this
order:
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1. Grind all hot roll scale adjacent to the bevel, 1” on the front and ¼” back side of the test plate.
2. Grind off all oxidation on the bevel to bare metal. Re-check the bevel angle for the correct angle.
3. Grind all the hot scale off the backing bar to clean metal.
4. The inspector will check the preparation before fitting-up test pieces.
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The bevels were tacked together, the root opening was set with two 1/8 electrodes, and then the plates were inspected.
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5. After the fit-up is completed the inspector will check all the fit-up specifications
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I put the test plates into the overhead position and they were
inspected and marked with a white marker. This is done so the plates are
not moved in any way while welding or grinding.
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6. Now the test will be placed in the fixed position. The test
piece will be marked in position with a marker and the inspector may see
the test anytime during the testing. (DURING THE TEST, THE PIECES SHALL
NOT BE MOVED IN ANY DIRECTION AND OR REMOVED FROM THE TESTING PLACE
WITHOUT THE INSPECTORS APPROVAL.)
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SMAW 4G Certification Welding Techniques
Overhead Root Pass Welding Techniques
To start the root pass I positioned myself in a way that I can weld
toward myself. The first picture is exactly my view from behind the
helmet while I am welding. The root took two and a half E7018 electrodes
and had two restart. I did a weave technique holding the sides of the
bevel until the arc of the electrode would roll and washes into the
bevel. If I remember correctly I held each side for about one second.
The second picture is the first root weld with the slag covering. Once I
put in the root I cleaned it with a chipping hammer and wire wheel. The
root was then inspected because the procedure stated:
7. The root pace shall be inspected.
This is where I forgot to take pictures. After that I did a light
grinding of the root to ensure there were no slag inclusions and that
is in the third picture.
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Overhead Fill Pass Welding Techniques
Before doing the fill pass I let the plate cool till I could barely
touch it with my bare hand. On the fill pass I used a wide weave
technique holding the sides briefly. It took six E7018 electrodes and
five restarts. Since the fill pass came almost to the top of the bevel
the slag just popped off by itself and all I had to do is just go over
it with a wire wheel. |
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Overhead Welding Techniques for the Cap and Cover Pass
Before welding the cap I let the plate cool until I could touch it.
When welding the cap I used stringer beads. The technique I used was
just start the arc and shove the rod into the joint. There was no
manipulation of the electrode or any hand movement. I literally let the
rod do all of the work! The way this works is the rod is pointed away
from you on a 15 degree angle and as the rod burns all you do is keep
applying pressure on it till the weld is finished. This is how I
typically do most of my welds outside of a welding certification. The
cap took four electrodes and had no restarts. To clean the slag all it
took was just a light tap with a chipping hammer and it came off. After
I finished the cap I cleaned it with a wire brush. |
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I inspected the cap while still in position and noticed a few spots
that had excessive weld reinforcement. I took a 1/8 electrode to measure
the height of the weld and marked a few areas that I needed to grind. I
grinded the excessive weld reinforcement until the 1/8 electrode was
even with the height of the cap. I did this because the welding
procedure states:
“The face of the weld shall be flush with the surface of the base
metal, and the weld shall merge smoothly with the base metal. Undercut
shall not exceed 1/32 in. (1 mm). Weld reinforcement shall not exceed 1/8 in. (3 mm)”
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Most welding certification procedures allow one repair to be given
after the weld is inspected. Once the test is inspected and you do a
repair there are no more fixes after that. This is a perfect example of
why you should inspecting you own welds. If you find something wrong
and fix it, it is fine, but don’t expect to get any slack if someone has
to do your job. With a welding certification after the first inspection
that second repair needed results in total test failure. And no you do
not get to bend it! Don't take this like you are allowed to do many
repairs. If your welds need a lot of repairs and the inspector notices
you struggling you may fail on the spot. Not all welding procedures
allow repairs or even the use of a grinder or wire wheel!
Preparation of the Test Coupons
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The test coupons were pre paired exactly like my 3G welding
certification. I marked the test specimens, cut them on a band saw, took
a punch and marked the center of the welds, removed the backing bar,
and grinded down the root and face to the thickness of the test
material. |
The Bend Test
The first bend done was the root bend followed by the face bend. Both
pieces passed and I did not need the alternate. As you can see below
the test coupon were not completely clean. I had a few minor defects
that were well within the AWS D1.1 acceptance criteria. The openings
were less then 1/32 of an inch so they did not count as discontinuities.
I asked why these pieces had these openings and I was told these are
common when using weave techniques.
Here are the acceptance criteria for the bend test in the words of the American Welding Society.
“Acceptance Criteria for Bend Tests. The convex surface of the
bend test specimen shall be visually examined for surface
discontinuities. For acceptance, the surface shall contain no
discontinuities exceeding the following dimensions:
(1) 1/8 in. (3 mm) measured in any direction of the surface
(2) 3/8 in. (10 mm) – the sum of the greatest dimensions of all
discontinuities exceeding 1/32 in. (1 mm) , but less than or equal to
1/8 in (3 mm).
(3) ¼ in. (6 mm) – the maximum corner crack resulting from
visible slag inclusions or other fusion type discontinuities, then 1/8
in. (3 mm) maximum shall apply
Specimens with corner cracks exceeding ¼ in. (6 mm) with no
evidence of slag inclusions or other fusion type discontinuities shall
be disregarded, and a replacement test specimen from the original
weldment shall be tested.”
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Here are the results of the bend test. As you can see there are some minor openings but well within the acceptance critera. |
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MIG Welder Certification
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