UGIALLOY® 686 – High‑Performance Chromium‑Molybdenum‑Tungsten Filler Wire for Superior Corrosion Resistance

UGIALLOY® 686 filler wire contains high quantities of chromium, molybdenum and tungsten, enabling it to be used for welds or claddings that are more resistant to corrosion and/or oxidation than the majority of nickel-based grades in many highly corrosive environments (chemical, waste treatment, fertilizers, etc.). For example, its general corrosion resistance in very harsh aqueous environments is considered higher than that of Alloy 59 (which is itself much higher than that of alloy 625).

UGIALLOY® 686 is used for the homogenous welding of UNS N06686 and to weld many Ni-Cr-Mo alloys with a low C content and fewer alloying elements than UNS N06686, as well as for welding superaustenitic and super-duplex stainless steels.

Finally, UGIALLOY® 686 is used for coating steels or stainless steels to improve corrosion and/or oxidation resistance in very harsh environments (for example for incinerator parts).

Properties

General

Property	Temperature	Value
Density	23.0 °C	8.72 g/cm³

Mechanical

Property	Temperature	Value
Charpy impact energy, V-notch	-40.0 °C	80 - 90 J
Elastic modulus	20.0 °C	207 GPa
	100.0 °C	205 GPa
	200.0 °C	197 GPa
	300.0 °C	193 GPa
	400.0 °C	185 GPa
	500.0 °C	183 GPa
	600.0 °C	173 GPa
	700.0 °C	165 GPa

Elongation	23.0 °C	40 %
Tensile strength	23.0 °C	798 MPa
Yield strength	23.0 °C	507 MPa

Thermal

Property	Temperature	Value
Coefficient of thermal expansion	23.0 °C	1.1E-5 - 1.86E-5 1/K
	600.0 °C	2.14E-5 1/K

Specific heat capacity	20.0 °C	373 J/(kg·K)
	100.0 °C	389 J/(kg·K)
	200.0 °C	410 J/(kg·K)
	300.0 °C	431 J/(kg·K)
	400.0 °C	456 J/(kg·K)
	500.0 °C	477 J/(kg·K)
	600.0 °C	498 J/(kg·K)
	700.0 °C	519 J/(kg·K)

Thermal conductivity	20.0 °C	9.82 W/(m·K)
	100.0 °C	11 W/(m·K)
	200.0 °C	12.8 W/(m·K)
	300.0 °C	14.8 W/(m·K)
	400.0 °C	16.6 W/(m·K)
	500.0 °C	18.6 W/(m·K)
	600.0 °C	21.4 W/(m·K)
	700.0 °C	23.5 W/(m·K)

Electrical

Property	Temperature	Value
Electrical resistivity	20.0 °C	1.24E-6 Ω·m
	100.0 °C	1.25E-6 Ω·m
	200.0 °C	1.26E-6 Ω·m
	300.0 °C	1.26E-6 Ω·m
	400.0 °C	1.27E-6 Ω·m
	500.0 °C	1.29E-6 Ω·m
	600.0 °C	1.3E-6 Ω·m
	700.0 °C	1.28E-6 Ω·m

Magnetic

Property	Temperature	Value	Comment
Relative magnetic permeability	23.0 °C	1 [-]	at 200 Oe (15.9 kA/m)

Chemical properties

Property	Value	Comment
Aluminium	0.5 %	max.
Carbon	0.01 %	max.
Chromium	19 - 23 %
Copper	0.5 %	max.
Iron	2 %	max.
Manganese	0.1 %	max.
Molybdenum	15 - 17 %
Nickel	49 %	min.
Phosphorus	0.02 %	max.
Silicon	0.08 %	max.
Sulfur	0.02 %	max.
Titanium	0.25 %	max.
Tungsten	3 - 4.4 %

Technological properties

Property

Application areas

Coatings or weldings in highly corrosive environments such as:

Chemical treatments (including heat exchangers, reactors, evaporators, etc.)

Pollution removal (including columns, pipes, housings, etc.)

Paper manufacturing industry

Waste treatment

Petrochemical

Harsh marine environment

Corrosion properties

General corrosion: The table below gives the general corrosion rates in mm/year for different assemblies made from UGIALLOY® 686 and other filler wires kept in an acid environment of 10% H₂SO₄ + 2% HCl at 80°C for 7 days.

Base metal	Filler wire	Corrosion rate (in mm/year)
Base metal	Filler wire	GTAW across thin sheets	GMAW across thin sheets	SAW across thick sheets
UNS N06686	UGIALLOY® 686	0.4	0.5	0.6
UNS N06022	UGIALLOY® 686	1.2	1.2	1.3
UNS N06022	UGIALLOY® 22	1.3	1.3	1.5
UNS N06276	UGIALLOY® 686	0.7(a)	0.6	0.8
UNS N06276	UGIALLOY® 276	0.7	0.7	0.9
(a) Slight attack in the heat affected zone

Localized corrosion

Pitting corrosion: The table below gives the pitting corrosion rates in terms of maximum pitting depth in mm/year for different assemblies made from UGIALLOY® 686 and other filler wires kept in an SO₂ + 26% NaCl saturated environment at 80°C for 14 days.

Base metal	Filler wire	Maximum attack depth (in mm/year): base metal /weld metal zone
Base metal	Filler wire	GTAW across thin sheets	GTAW across thick sheets	GMAW across thin sheets	GMAW across thick sheets	SAW across thick sheets
UNS N06686	UGIALLOY® 686	0/0	0/0	0/0	0/0	0/0
UNS N06022	UGIALLOY® 686	0.4/0.1	0.3/0	0.2/0	0.4/0.1	0.4/0
UNS N06022	UGIALLOY® 22	0.3/0.5	0.4/0.7	0.2/0.3	0.6/0.6	0.4/0.8
UNS N06276	UGIALLOY® 686	0.8/0.4	0.7/0.5	0.6/0.5	0.7/0.5	0.7/0.3
UNS N06276	UGIALLOY® 276	0.7/0.8	0.6/0.9	0.4/0.6	0.6/1.0	0.5/1.1

The table below gives the pitting corrosion rates in terms of maximum pitting depth in mm/year for different assemblies made from UGIALLOY® 686 and other filler wires kept in an 11.9% H₂SO₄ + 1% CuCl2 environment at 103°C for 7 days.

Base metal	Filler wire	Maximum attack depth (in mm/year): base metal /weld metal zone
Base metal	Filler wire	GTAW across thin sheets	GTAW across thick sheets	GMAW across thin sheets	GMAW across thick sheets	SAW across thick sheets
UNS N06686	UGIALLOY® 686	0/0	0/0	0/0	0/0	0/0
UNS N06022	UGIALLOY® 686	0.4/0.1	0.3/0	0.2/0	0.4/0.1	0.4/0
UNS N06022	UGIALLOY® 22	0.3/0.5	0.4/0.7	0.2/0.3	0.6/0.6	0.4/0.8
UNS N06276	UGIALLOY® 686	0.8/0.4	0.7/0.5	0.6/0.5	0.7/0.5	0.7/0.3
UNS N06276	UGIALLOY® 276	0.7/0.8	0.6/0.9	0.4/0.6	0.6/1.0	0.5/1.1

Intergranular corrosion: The table on the right side of the material page gives the intergranular corrosion rates in mm/year for different assemblies made from UGIALLOY® 686 and other filler wires after 24 h under the conditions specified in ASTM G28B.

Other

Available products:

Product	Dimensions
Welding rods	∅ 1.0 to 4.0 mm
Welding wire spools (BS300)	∅ 0.8 to 1.6 mm

For other dimensions or products, please the supplier.

Welding

The tables below give the typical welding conditions to be used for UGIALLOY® 686 during MIG and TIG welding with filler wire.

GMA welding

Transfer type	Wire diameter (mm)	Wire speed (m/min)	Welding voltage (V)	Welding current (A)
Non-pulsed spray	0.9	11.5-15	26-32	180-250
	1.2	6.0-9.0	26-32	220-300
	1.6	3.5-5.7	27-33	250-350
Pulsed spray	0.9	7.0-10.2	19-22	90-140
	1.2	2.5-5.5	21-26	120-190
	1.6	1.8-3.5	23-28	160-240
Shielding gas: Ar or mixture of Ar/He with a flow rate of 17 to 23 l/min

GTA welding

Wire / rod diameter (mm)	Tungsten electrode diameter (mm)	Shielding gas feed nozzle diameter (mm)	Welding current (A)
1.6	1.6-2.4	9.5-16	90-160
2.4	1.6-2.4	9.5-16	100-190
3.2	2.4-3.2	12.5-16	110-210

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