N-18

Specification

AWS Specification: AWS A5.1 E7018
JIS Specification: D5016
Other Specification: DIN E5153B10

Description

N-18 is an iron powder low hydrogen type electrode containing a large amount of iron powder in coating flux to give higher deposition rates
Deposited metal gives excellent mechanical properties, crack resistance, and X-ray quality
Good weldabilities, such as smooth and stable arc, easy slag removal, low spatters, and nice bead appearance

Application

All position welding of 50 KG/mm² high tensile strength steels
Ships
Steel frames
Bridges
Pressure vessels

Remarks

N-18 stick electrodes require a drag to 1/16 inches maximum arc length to obtain the desired mechanical properties and weld quality

An arc length of 1/8 inches or longer may result in porosity and serious deterioration of impact properties

Take the backstep method or strike the arc on a small steel plate prepared for this particular purpose to prevent blowholes at the arc starting

Polarity: Use DC(+) whenever possible, with 5/32 inches and smaller sizes. Use AC with the larger sizes for the best operating characteristics (min. O.C.V. 70 Volts), but DC(+) can also be used

Downhand: On the first pass, or whenever it is desirable to reduce admixture with abase metal of poor weldability, use low currents. On succeeding passes, use currents that provides best operating characteristics. Drag tip electrode lightly or hold as short an arc as possible, 1/16 inches maximum when optimum impacts and X-ray quality are required. Do not use a long arc at any time because this type of electrode relies principally on molten slag for shielding. Stringer beads or small weave passes are preferred to wide weave passes. Layers should be kept as thin as possible (3/16 inches max.) for best properties. When starting a new electrode, strike the arc ahead of the crater, move back into the crater, and then proceed in the normal direction. Use higher currents on AC than DC. Govern travel speed by the desired bead size

Vertical: Weld vertical-up with 5/32 inches and smaller sizes. Use a triangular weave for heavy single-pass welds. For multi-pass welds, first deposit a stringer bead using a slight weave. Deposit additional layers with a side-to-side weave, hesitating at the sides long enough to fuse out any small slag pockets and to minimize undercut.

Do not use a whip technique or take the electrode out of the molten pool. Travel slow enough to maintain the shelf without causing metal to spill. Use currents in the low to middle portion of the range, depending on joint design and plate thickness

Overhead: Use 5/32 inches and smaller electrodes. Deposit stringer beads using a slight circular motion in the crater. Motions should be slow and deliberate. Move fast enough to avoid spilling weld metal, but do not be alarmed of some slags spills. Use currents in the lower portion of the range.

Technical Data

TYPICAL CHEMICAL COMPOSITION OF ALL WELD METAL DEPOSITS (%):

C	Si	Mn	P	S
0.07	0.60	0.97	0.013	0.010

TYPICAL MECHANICAL PROPERTIES OF ALL WELD METAL DEPOSITS:

Yield Point N/mm² (KSI)	Tensile Strength N/mm² (KSI)	Elongation %	Impact Value °C, J (°F, Ft-Lbs)
510 (74)	590 (86)	29	-29°, 160 (-20°, 118)

TYPICAL DIFFUSIBLE HYDROGEN OF WELD METAL:

Diameter (mm)	Current (amp)	Re-drying Condition	Diffusible Hydrogen Mean Value (cc./100g)
4.0	AC	350ºC x 0.5 hrs.	3.0

SIZE AND RECOMMENDED CURRENT RANGE: AC, DC (+)

DIAMETER (mm)		2.5	3.2	4.0	5.0	6.0
LENGTH (mm)		350	350	400	450	450
Current Amp	Flat	70 - 100	100 - 140	150 - 200	190 - 240	250 - 320
Current Amp	Vertical & Overhead	60 - 90	80 - 120	120 - 160	140 - 180	-

Welding Positions:	ALL POSITIONS EXCEPT VERTICAL DOWN
Approvals:	ABS, BV, DNV, LRS

NOTE:

The information contained or otherwise referenced herein is presented only as “typical” without guarantee or warranty, and Industrial Welding Corporation expressly disclaims any liability incurred from any reliance thereon. Typical data and test results for mechanical properties, deposit, or electrode composition and other properties were obtained from a weld produced and tested according to prescribed standards and should not be assumed to be the expected results in a particular application or weldment. Actual results will vary depending on many factors, including, but not limited to, weld procedure, plate chemistry and temperature, weldment design, and fabrication methods. Users are cautioned to confirm by qualification testing, or other appropriate means, the suitability of any welding consumable and procedure before use in the intended application.