Hyundai Welding S-9015.B9 E9015-B91 P91 Electrode

Overview

The Hyundai Welding S-9015.B9 is a low hydrogen stick electrode for modified 9 % chromium – 1 % molybdenum steel, the material usually called grade 91. It is classified to AWS A5.5 / ASME SFA-5.5 E9015-B91, JIS Z 3223 E6215-9C1MV and EN ISO 3580-A E CrMo91 B 4 2 H5. Hyundai Welding states good creep resistance at high temperature and a maximum service temperature of 650 °C (1202 °F).

Seven Star LLC supplies the Hyundai Welding S-9015.B9 from Muscat to power stations, HRSG builders, refineries and maintenance contractors in Oman and the GCC. This page is based on the manufacturer datasheet, which you can download below, with general P91 welding background clearly labelled.

Grade 91 Background

As general knowledge, grade 91 is a creep-strength-enhanced ferritic steel. Small additions of vanadium, niobium and nitrogen to a 9Cr-1Mo base give fine, stable precipitates that provide much higher creep strength than older chrome-moly grades, allowing thinner walls in high-temperature steam systems. That performance depends on the right microstructure, so welding procedures for this class are among the most tightly controlled in industry.

Typical P91 practice includes significant preheat, controlled interpass temperature, cooling to complete the transformation before PWHT, and a tempering PWHT in a narrow temperature window. Filler chemistry matters too: the Hyundai Welding S-9015.B9 deposit contains 8.9 % Cr, 0.99 % Mo, 0.20 % V, 0.04 % Nb and 0.03 % N, matching the base alloy design. All thermal parameters must come from the code and the qualified procedure.

Hyundai Welding S-9015.B9 Datasheet Summary

Full typical chemistry is 0.10 % C, 0.27 % Si, 0.85 % Mn, 0.009 % P, 0.006 % S, 0.03 % Cu, 0.29 % Ni, 8.9 % Cr, 0.99 % Mo, 0.04 % Nb, 0.01 % Al, 0.20 % V and 0.03 % N. After PWHT at 760 °C for 2 hours, typical results are 603 MPa (87 ksi) yield, 747 MPa (108 ksi) tensile, 24 % elongation and 55 J (41 ft·lbs) at room temperature. After 760 °C for 4 hours they are 611 MPa (89 ksi), 732 MPa (106 ksi), 24 % and 60 J (44 ft·lbs).

The Hyundai Welding S-9015.B9 is a low hydrogen electrode with HDM of 5 ml/100 g or less, uses DC± polarity and performs well on DCEP according to the manufacturer. It is rated for 1G, 2F, 3G and 4G. Four diameters are listed, 2.6, 3.2, 4.0 and 5.0 mm, packed in 5 kg (11 lbs) packets, standard or vacuum, and 20 kg (44 lbs) cartons. Redrying is 300 to 350 °C for 0.5 to 1 hour. No approval marks are printed on this datasheet.

Key Features

The Hyundai Welding S-9015.B9 datasheet highlights:

• Good creep resistance at high temperature.
• Maximum service temperature of 650 °C (1202 °F).
• Low hydrogen deposit with HDM of 5 ml/100 g or less, reflected in the H5 symbol.
• Good performance with DCEP.
• Vanadium, niobium and nitrogen bearing 9Cr-1Mo deposit chemistry.
• Published properties after two PWHT durations at 760 °C.
• Diameters from 2.6 mm to 5.0 mm.
• Application areas of 9 % Cr – 1 % Mo steel, pressure vessels and power plants.

Applications

The Hyundai Welding S-9015.B9 is used on main steam and hot reheat piping, headers and HRSG high-pressure sections built in grade 91, and on related pressure vessels and fittings. Combined-cycle power and water plants in Oman, including the large facilities that supply the main grid and desalination, typically include grade 91 piping that needs qualified repair and modification work during outages.

Seven Star LLC can also supply welding power sources such as the Lincoln Electric Power Wave S500 and the ESAB Rebel EMP 285ic, along with carbon steel consumables such as the LongTeng EL8 SAW wire. See all stick products in our welding electrodes category.

Why an EXX15 Coating

In AWS terminology, the last two digits of the classification describe the coating and usable current. As general knowledge, an EXX15 electrode has a low hydrogen sodium-based coating designed for DC electrode positive, whereas an EXX18 has an iron powder potassium-based coating that also works on AC. The Hyundai Welding S-9015.B9 follows that pattern: the datasheet polarity field shows DC± and notes good performance with DCEP, and it has no AC rating. Welders setting up inverter power sources should select DC+ unless the qualified procedure states otherwise.

Grade 91 joints are usually checked after PWHT by hardness testing and, on critical pressure parts, by positive material identification of the weld metal to confirm chromium and molybdenum content. Because the published Hyundai Welding S-9015.B9 data includes results after both 2 and 4 hours at 760 °C, engineers can see how longer tempering lowers tensile strength slightly while raising room-temperature impact energy, which is useful when planning repair sequences that may involve more than one PWHT cycle.

Technical Specifications

All figures are typical values from the Hyundai Welding S-9015.B9 datasheet.

Welding Current

Handling

General practice for H5 grade 91 electrodes is to keep them sealed until use, redry at the manufacturer temperature, which for the Hyundai Welding S-9015.B9 is 300 to 350 °C for 0.5 to 1 hour, and hold them in heated ovens with strict exposure limits. Batch traceability and certificate review are normally required on pressure parts.

Planning the consumable quantity in advance also matters, because thick grade 91 joints take many passes and interruptions while waiting for redried electrodes can force the joint below the minimum preheat.

Datasheet

The official Hyundai Welding S-9015.B9 datasheet, covering classification, chemistry, PWHT properties, parameters and packaging, is available for download on this page.

Call To Action

For a quotation on the Hyundai Welding S-9015.B9, send Seven Star LLC your diameters, quantities and certificate requirements. Our team in Muscat supports power and process plant customers across Oman and the GCC with engineering support.