Lincoln Electric Jet-LH 78 MR E7018 H4R Low Hydrogen Stick Electrode

Overview

Lincoln Electric Jet-LH 78 MR is a mild steel, low hydrogen stick electrode for shielded metal arc welding (SMAW), classified AWS E7018 H4R. It is listed by Lincoln Electric for general fabrication and offers smooth arc performance in all positions except vertical down. The datasheet covers both the standard 50 lb easy open can and the retail small packaging (RSP) tubes, which makes the electrode useful for large shops and for site crews that buy smaller cartons.

Seven Star LLC supplies Lincoln Electric Jet-LH 78 MR to workshops, maintenance contractors and project teams across the Sultanate of Oman and the GCC. Our Muscat team can share the manufacturer datasheet, explain how this grade differs from other E7018 products in the Lincoln range, and advise on holding and re-drying practice for low hydrogen electrodes.

Classification and Process Background

An E7018 electrode is a stick electrode with a minimum tensile strength of 70 ksi, usable in all positions, with a low hydrogen basic coating and iron powder for productivity. The suffix H4R in the classification of Lincoln Electric Jet-LH 78 MR indicates that the diffusible hydrogen level does not exceed 4 mL per 100 g of weld metal and that the electrode meets the moisture resistance requirement of the standard. The datasheet prints a typical diffusible hydrogen result of 1 to 3 mL per 100 g, well below the 4.0 mL limit.

Low hydrogen electrodes such as Lincoln Electric Jet-LH 78 MR are chosen for steels that are thick, restrained or of higher carbon equivalent, because they reduce the risk of hydrogen assisted cold cracking in the heat affected zone. They also deposit tough weld metal that tolerates low temperature impact testing. For mild steel plate, pipe and structural sections, Lincoln Electric Jet-LH 78 MR provides that protection at a competitive cost for general fabrication.

Engineering Design and Packaging

Lincoln Electric Jet-LH 78 MR is a mild steel core wire coated with a low hydrogen flux coating. Lincoln Electric lists diameters of 3/32 inch (2.4 mm) at 12 inch (300 mm) length, 1/8 inch (3.2 mm) and 5/32 inch (4.0 mm) at 14 inch (350 mm) length for the 5 lb tube and 20 lb master carton, and a wider 3/32 to 1/4 inch range for 50 lb easy open cans, with 18 inch (450 mm) length for 1/4 inch. The datasheet explicitly notes that the retail small packaging products carry AWS compliance, but unlike the standard products they have no other agency approvals.

That note is important for buyers: if a project requires ship classification or other third party approvals for the electrode, specify the standard can package and confirm the approvals with the supplier before ordering. The manufacturer reference packages are not a statement of Seven Star stock, so please request current availability.

Key Features of Lincoln Electric Jet-LH 78 MR

The following points are printed in the Lincoln Electric Jet-LH 78 MR datasheet:

• Smooth arc performance, giving welders good control and a consistent bead profile.
• Low hydrogen classification AWS E7018 H4R with typical diffusible hydrogen of 1 to 3 mL per 100 g.
• Welding in all positions except vertical down on either DC electrode positive or AC.
• Typical as-welded yield strength of 415 to 570 MPa and tensile strength of 495 to 640 MPa.
• Typical Charpy V-notch results of 156 to 353 J at -29 C, far above the 27 J minimum requirement.
• Conformances including ASME SFA-A5.1, ABS E7018, Lloyd’s Register 3YM H5, DNV 3 YH5, GL 3YH5, BV 3YHHH and CWB E4918-1 for the standard packaging.
• Choice of 5 lb tubes for site work and 50 lb cans for shop production.

Industrial Applications in Oman and the GCC

General fabrication is the application listed by the manufacturer, and for Lincoln Electric Jet-LH 78 MR that covers structural steel, brackets, supports, skids, tank attachments and repair welding on mild steel. In Oman the electrode is useful for maintenance crews in the industrial zones at Sohar, Rusayl and Salalah, for site erection teams on gas and power projects, and for workshops that need a dependable E7018 for root and fill passes on carbon steel pipe and plate. Because it is a low hydrogen grade, it also appears on welding procedures for pressure retaining parts when the specification allows.

Seven Star LLC supplies Lincoln Electric Jet-LH 78 MR together with welding machines and spares. The Lincoln Electric Power Wave S500 supports stick welding within its multi-process range, and the ESAB Rebel EMP 285ic is a portable platform for site crews. Plant owners can also see industrial items such as the Kobelco Lubricator Assembly on our catalogue.

Operating Procedures Printed by the Manufacturer

Lincoln Electric prints current ranges for every diameter. On DC electrode positive, which it names as the preferred polarity, the typical amperage is 65 to 100 A for 3/32 inch, 110 to 160 A for 1/8 inch, 130 to 200 A for 5/32 inch, 180 to 270 A for 3/16 inch and 300 to 400 A for 1/4 inch. On AC the printed ranges are 70 to 105 A, 120 to 170 A, 140 to 230 A, 210 to 290 A and 325 to 420 A. Weld vertical and overhead joints in the lower part of each range and settle the final parameters through a qualified procedure.

Technical Specifications of Lincoln Electric Jet-LH 78 MR

Everything in this table is quoted from the Lincoln Electric Jet-LH 78 MR datasheet; the typical results are as-welded values and do not guarantee performance in a specific application.

Keeping the Coating Dry

Moisture is the enemy of any basic coating. Welders handling Lincoln Electric Jet-LH 78 MR on site should leave unopened tubes and cans sealed, move only what a shift needs into a heated rod box, and send electrodes that sat out overnight for re-baking under the maker’s written instructions. A short arc and a back stepping start help prevent porosity at the beginning of a pass with any E7018 type. This is general practice and not a Lincoln Electric warranty statement.

Call To Action

Planning a purchase of Lincoln Electric Jet-LH 78 MR? Tell Seven Star LLC which diameter, carton or can, quantity and approval paperwork you need. We will return a formal quotation with delivery terms for Oman and the GCC. The manufacturer datasheet can be downloaded from this page. Seven Star LLC is a trusted supplier of Lincoln Electric products, backed by engineering support in Muscat, and welcomes your enquiry.