Adding to very elaborated info by Mr. Hegazy.
There are many versions of HSLA steel-
older version like (USS T1, HY80, HY100)
new versions like (weathering steels, microalloyed ferrite/pearlite steels, as-rolled pearlitic steels, low-carbon bainitic steels, dual phase (as you mentioned) steels and inclusion shape controlled steels.) They are classified as microalloy steel.
The microalloyed HSLA steels during fabrication result in fine grained (enhanced toughness) structures with increasing yield strength obtained thru precipitation strengthening.
As with any welding operation, heat will alter grain size and the distribution/location of phases and preciptates within the HSLA steel microstructure, thus affecting desired properties. Keeping the heat input prior to (preheat temperature) and during welding (interpass temperature) to the minimum recommended by the steel manufacturer is the key to maintaining a localized heat affected zone.
Regards
Manpreet Singh
Welding Engineer
Spiecapag
On Tue, 27 Jul 2010 14:42:50 +0530 wrote
>
Just
to add Metallurgy behind HSLA.
Metals and alloys get deformed when dislocations
are forced to move by application of force.
Addition of small amount of carbide forming elements eg. Nb, V, Ti
etc added total amount 0.20% max and this fine dispersion of alloy carbides will
restrict the movement of dislocations and results in strengthening by
precipitation hardening.
Regds/Jignesh
>
From: materials-welding@googlegroups.com
[mailto:materials-welding@googlegroups.com] On Behalf Of MOHAMED
HEGAZY
>Sent: Tuesday, July 27, 2010 1:44 PM
>To:
materials-welding@googlegroups.com
>Subject: Re: [MW:6141] HSLA
Welding.
>
>
Dear Limesh,
HSLA Steels are Microalloyed Steels formulated with small
amounts of some alloying elements ( Niobium Nb, Vanadium V & Aluminum
Al )to provide higher strength, better toughness & Weldability and in
some cases greater resistance to specific corrosion mechanisms in specific
environments than Ordinary Carbon Steels.
Usually used in as rolled or Normalized Conditions &
rolling process is integrated in developing final Mechanical
Properties.
Special rolling practices such as Controlled Rolling known as
Thermo Mechanical Controlled Processing TMCP had been devised for
enhancing Mechanical & Metallurgical performance for this category of
steels.
Typical Yield Strengths range is 40 up to 110 Ksi & Typical Tensile Strengths
range is 60 up to 120 Ksi .
Common Grades on API are: 5L Gr X 60,X 70 & X
80.
Common Grades on ASTM are : A 353 , A 735 & A
736
I believe that both HSLA 65 & API X65 are the
same.
Some Precautions to be taken during welding :
1-Preheat to be used based on Thickness, Carbon Equivalent
& Welding Process…..
2-Low Hydrogen Practices (Proper cleaning, packaging for
fillers & avoid any Hydrogen Contamination sources
)
to be followed with ARC Welding
Processes ( Gas shielded Arc Processes GTAW,GMAW or PAW are Preferred rather than Slag
Shielded Processes SMAW,SAW or
FCAW ).
3-Cellulosic Electrodes can be used with some API Grades (
Low Carbon Content Grades ).
Thanks
& Regards
>
>
Mohamed.Hegazy
QA QC Welding
Engineer
AWS Certified Welding Engineer
CWEng.
TWI CSWIP Welding Inspection
3.1.
VSA Consortium
( VEOLIA, SAIPEM & Aljaber )
QATAR
SHELL PEARL GTL Project
>Ras Laffan
,Qatar
QATAR : +9743694501
EGY:
+20142345614
: MH_W_Inspect@Yahoo.COM
>
>
>--- On Tue, 7/27/10, Ali Asghari
>
>From:
Ali Asghari
>Subject: Re: [MW:6139]
HSLA Welding.
>To: materials-welding@googlegroups.com
>Date:
Tuesday, July 27, 2010, 9:32 AM
>
>
#yiv2015797043 DIV {
MARGIN: 0px
}
these steel are refinement by adding microalloys such V,Al,Nb,Ti
& thermo mechanically heat treatment to increse toughness &
strength simultanously.
>HY-80,HY-100 & X-100 are examples of
these steels.
>during of welding of these steels, the minimum H.I
SHALL BE USED to prevent growth grain.
>
>
From: limesh M
>To: Materials & Welding
>Sent: Tue, July 27, 2010 10:15:16
AM
>Subject: [MW:6137]
HSLA Welding.
>
>Dear All,
>
>I have heard a lot about of
HSLA(High Strength Low Alloy) and it
>confusing me a lot.
>
>Can
anyone give a proper defenition for HSLA steel ?
>
>What are all the
common grades in API,ASME,ASTM,AISI comes under HSLA
>steel category
?
>
>HSLA-65 and API X65 are same material?
>
>What are all the
precautions we have to follow during HSLA welding ?
>
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