{"product_id":"lincoln-ironarc-7018-mr-x-14-smaw-welding-rod","title":"Lincoln E7018 H4R (IronArc 7018 MR x 14 SMAW Welding Rod)","description":"\u003cp\u003eLincoln IronArc 7018 MR is a moisture-resistant E7018 H4R welding rod designed for structural, pressure vessel, and general fabrication welding where low hydrogen content (≤ 4 mL\/100g) and extended exposure tolerance are needed. With a 72,000 psi minimum tensile, DCEP or AC operation, and Lincoln's MR (moisture-resistant) flux coating, IronArc 7018 MR bridges the gap between standard E7018 and premium Excalibur 7018 MR — delivering proven H4R performance with an economical package suited to high-volume structural welding shops and contractors working in field conditions.\u003c\/p\u003e\n\n\u003ch2\u003eWhat Is the Lincoln IronArc 7018 MR E7018 H4R Welding Rod?\u003c\/h2\u003e\n\u003cp\u003eIronArc 7018 MR is Lincoln Electric's value-positioned E7018 moisture-resistant SMAW electrode. The AWS classification E7018 H4R decodes as: \"E\" = electrode; \"70\" = 72,000 psi minimum tensile; \"1\" = all-position; \"8\" = low-hydrogen iron-powder covering, AC or DCEP; \"H4R\" = diffusible hydrogen ≤ 4 mL\/100g weld metal, with moisture-resistant coating. The H4R designation is critical for structural welding under AWS D1.1, ASME Section IX, and various bridge codes that mandate low-hydrogen filler for thick-section, high-restraint, and hydrogen-cracking-sensitive applications. IronArc 7018 MR occupies a specific market position: it provides the same essential H4R credentials as Lincoln's premium Excalibur 7018 MR but at a more accessible price point, making it a popular choice for fabrication shops and structural contractors who weld high volumes of E7018 under AWS D1.1 and need reliable hydrogen control without the premium Excalibur pricing on every pound of electrode consumed.\u003c\/p\u003e\n\u003cp\u003eThe \"MR\" moisture-resistant coating means the flux binder resists humidity absorption at a higher rate than standard E7018, extending the permitted out-of-oven exposure time. This is particularly valuable in field welding, bridge erection, and coastal or tropical construction environments where maintaining oven access between every rod change is impractical.\u003c\/p\u003e\n\n\u003ch2\u003eAWS Classification \u0026amp; Mechanical Specs — E7018 H4R Welding Rod\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eAWS Classification\u003c\/td\u003e\n\u003ctd\u003eE7018\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eH-Designation\u003c\/td\u003e\n\u003ctd\u003eH4R (≤ 4 mL\/100g diffusible H2, moisture-resistant)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTensile Strength (min.)\u003c\/td\u003e\n\u003ctd\u003e72,000 psi (496 MPa)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eYield Strength (min.)\u003c\/td\u003e\n\u003ctd\u003e60,000 psi (414 MPa)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eElongation (min.)\u003c\/td\u003e\n\u003ctd\u003e22%\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCharpy CVN (−20°F)\u003c\/td\u003e\n\u003ctd\u003e20 ft·lbf minimum\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFlux Type\u003c\/td\u003e\n\u003ctd\u003eLow-hydrogen iron-powder, moisture-resistant\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCurrent\u003c\/td\u003e\n\u003ctd\u003eAC, DCEP\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePositions\u003c\/td\u003e\n\u003ctd\u003eAll (F, H, V-up, OH)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDiameters\u003c\/td\u003e\n\u003ctd\u003e3\/32, 1\/8, 5\/32, 3\/16 in\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eThe 20 ft·lbf Charpy CVN at −20 °F is a critical distinction between E7018 and non-low-hydrogen electrodes (E7014, E6013). This CVN classification makes E7018 H4R the required filler metal for bridges, offshore structures, seismic zones, and other applications governed by AASHTO, AWS D1.5, or lateral load design requirements.\u003c\/p\u003e\n\n\u003ch2\u003eBest Applications for IronArc 7018 MR E7018 Welding Rod\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAWS D1.1 structural steel fabrication\u003c\/strong\u003e — buildings, industrial structures, stadiums, and industrial equipment requiring low-hydrogen filler and CVN toughness.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBridge girder and component fabrication\u003c\/strong\u003e — AWS D1.5 bridge welding code applications requiring verified H4R low-hydrogen filler.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePressure vessel fabrication per ASME Section VIII\u003c\/strong\u003e — standard carbon-steel vessels where E7018 is the code-specified filler class.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eField welding on construction sites\u003c\/strong\u003e — the MR coating provides extended viability outside the oven for field welders who cannot maintain continuous oven access.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigh-restraint joints on thick plate\u003c\/strong\u003e — the H4R designation is mandatory for joints with high stiffness, high preheat, and thick cross-section where hydrogen-induced cracking risk is elevated.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeismic-zone construction\u003c\/strong\u003e — IBC and AISC seismic provisions require low-hydrogen, notch-tough weld metal in seismic force-resisting system connections.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eHow to Use IronArc 7018 MR — Amperage, Polarity \u0026amp; Position\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eDiameter\u003c\/th\u003e\n\u003cth\u003eAmperage Range\u003c\/th\u003e\n\u003cth\u003ePosition Notes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003e3\/32 in\u003c\/td\u003e\n\u003ctd\u003e65–100 A\u003c\/td\u003e\n\u003ctd\u003eRoot passes, sheet, tack\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e1\/8 in\u003c\/td\u003e\n\u003ctd\u003e90–140 A\u003c\/td\u003e\n\u003ctd\u003eGeneral structural fabrication\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e5\/32 in\u003c\/td\u003e\n\u003ctd\u003e120–175 A\u003c\/td\u003e\n\u003ctd\u003eFill passes, large fillets\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e3\/16 in\u003c\/td\u003e\n\u003ctd\u003e160–225 A\u003c\/td\u003e\n\u003ctd\u003eHeavy fill\/cap, flat\/horizontal\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003ePolarity:\u003c\/strong\u003e DCEP preferred; AC acceptable on most machines with minimum 70 V OCV. DCEP provides better arc stability and slightly better penetration than AC.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eArc length:\u003c\/strong\u003e Very short — 1\/2× to 1× electrode core diameter. E7018 is particularly sensitive to long arc length: a long arc introduces nitrogen, causes porosity, and spatter. The characteristic short arc and \"drag\" technique of E7018 is fundamental to its low-hydrogen performance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eInterpass temperature:\u003c\/strong\u003e Maintain preheat (typically 150–300 °F for A36–A572 Grade 50 per AWS D1.1) and do not allow interpass to exceed 450–500 °F for most structural applications. Verify per the applicable code and WPS.\u003c\/p\u003e\n\n\u003ch2\u003eStorage \u0026amp; Handling for E7018 H4R MR Electrodes\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSealed containers:\u003c\/strong\u003e Lincoln's hermetically sealed canisters maintain H4R condition indefinitely at room temperature in a dry area.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHolding oven (mandatory once opened):\u003c\/strong\u003e 250–300 °F. MR coating extends the permitted out-of-oven exposure time per AWS D1.1 Table 4.7. Consult Lincoln's MR electrode guide for specific exposure time tables.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRedrying:\u003c\/strong\u003e 700–800 °F for 1 hour if moisture exposure is suspected. Track cumulative exposure time carefully.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNever use non-oven-stored E7018 on H4R-required welds:\u003c\/strong\u003e Moisture-absorbed E7018 can exceed 16 mL\/100g diffusible hydrogen — the primary cause of delayed hydrogen cracking in structural welds.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCompatible Base Metals \u0026amp; Joint Types for E7018\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eASTM A36, A572 Grades 42–65 structural steel\u003c\/li\u003e\n  \u003cli\u003eASTM A709 Grades 36, 50, 50W bridge plate\u003c\/li\u003e\n  \u003cli\u003eASTM A514, A517 quenched-and-tempered plate (verify preheat per code)\u003c\/li\u003e\n  \u003cli\u003eASTM A516 Grades 55–70 pressure vessel plate\u003c\/li\u003e\n  \u003cli\u003eAPI 2W Grade 50 offshore platform plate\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAll groove and fillet joint types in all positions. IronArc 7018 MR is one of the most versatile structural electrodes available — the combination of H4R, all-position capability, CVN toughness, and MR coating covers virtually every structural welding requirement except the highest-specification Demand Critical welds (use Excalibur 7018 MR for those).\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions — Lincoln IronArc 7018 MR E7018 Welding Rod\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between IronArc 7018 MR and Excalibur 7018 MR?\u003c\/strong\u003e\u003cbr\u003e\nBoth are E7018 H4R moisture-resistant electrodes. Excalibur 7018 MR is Lincoln's premium tier with tighter chemistry control, enhanced arc characteristics, and tested performance for Demand Critical weld applications per AWS D1.8 seismic provisions. IronArc 7018 MR is the value tier — same H4R and MR credentials at a more economical price, well-suited for high-volume standard structural fabrication where Demand Critical specification is not required.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is diffusible hydrogen and why does H4R matter?\u003c\/strong\u003e\u003cbr\u003e\nDiffusible hydrogen (measured in mL\/100g of weld metal) is hydrogen that can migrate through the weld metal and HAZ after welding, concentrating at stress risers and creating hydrogen-assisted cold cracking (HACC). H4R limits diffusible hydrogen to ≤ 4 mL\/100g — the lowest standard classification under AWS. HACC can occur hours or days after welding on thick or restrained joints in high-strength steels, making H4R specification mandatory for many structural, bridge, and pressure vessel applications.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How long can I leave IronArc 7018 MR out of the oven on a job site?\u003c\/strong\u003e\u003cbr\u003e\nThe MR designation extends the permitted atmospheric exposure time relative to standard E7018. AWS D1.1 Table 4.7 defines maximum exposure times for low-hydrogen electrodes at various relative humidity levels. For H4R MR electrodes, exposure limits are typically 9 hours in environments up to 50 % RH. Consult Lincoln's published MR electrode exposure data for site-specific guidance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can I run IronArc 7018 MR on an AC buzz-box?\u003c\/strong\u003e\u003cbr\u003e\nYes, but only on AC machines with at least 70 V open-circuit voltage. At lower OCV, E7018 arc starts become inconsistent. Most modern AC transformers (Lincoln AC-225, Tombstone-style 225 A machines) meet this requirement. If your machine produces arc instability or frequent sticking with E7018, check OCV first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Is E7018 required for all structural welding?\u003c\/strong\u003e\u003cbr\u003e\nNot always. For applications on mild steel (A36) with low restraint and no notch-toughness code requirement, E6013 or E7014 may be acceptable. E7018 is required when: (1) the weld code specifies Low Hydrogen (AWS D1.1 Table 4.5 Category F); (2) the joint is highly restrained, thick, or on high-yield steel (A572-65, A514); (3) the application requires CVN notch toughness. Verify with the applicable code and project specification before substituting filler metal classes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What OCV (open circuit voltage) is needed to run E7018?\u003c\/strong\u003e\u003cbr\u003e\n70 V minimum OCV is the general industry standard for reliable E7018 arc starts. At lower OCV (e.g., 50–60 V), arc starts are erratic and the electrode tends to stick on contact. Engine-driven welders and modern inverters typically exceed 70 V OCV; verify your machine's OCV before running E7018 on an unfamiliar power source.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can IronArc 7018 MR be used for root passes on pipe?\u003c\/strong\u003e\u003cbr\u003e\nE7018 can be used for pipe root passes with a tight-fit, back-gouged, or ceramic-backed root configuration. For open-root pipe groove welds (no backing), the fast-freeze is less reliable than E6010\/E6011. Most pipe welding procedures use E6010 for the root and hot pass, then fill and cap with E7018. Consult the applicable WPS for root pass electrode specification.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\"@type\": \"Question\", \"name\": \"What is the difference between IronArc 7018 MR and Excalibur 7018 MR?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Both are E7018 H4R MR electrodes. Excalibur is the premium tier with tighter chemistry for Demand Critical applications. IronArc is the value tier with the same H4R and MR credentials for standard high-volume structural fabrication.\"}},\n    {\"@type\": \"Question\", \"name\": \"What is diffusible hydrogen and why does H4R matter?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Diffusible hydrogen migrates through weld metal and HAZ, causing hydrogen-assisted cold cracking hours or days after welding. H4R limits it to 4 mL\/100g — the lowest AWS classification, mandatory for thick, restrained, or high-strength steel applications.\"}},\n    {\"@type\": \"Question\", \"name\": \"How long can I leave IronArc 7018 MR out of the oven?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"AWS D1.1 Table 4.7 permits up to 9 hours exposure for H4R MR electrodes in environments up to 50% RH. Consult Lincoln's MR electrode exposure tables for site-specific guidance.\"}},\n    {\"@type\": \"Question\", \"name\": \"Can I run IronArc 7018 MR on an AC buzz-box?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes, on AC machines with at least 70V OCV. Below this, arc starts become inconsistent. Most modern 225A transformers meet this requirement.\"}},\n    {\"@type\": \"Question\", \"name\": \"What OCV is needed for E7018?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"70V minimum OCV for reliable arc starts. Below 60V, E7018 tends to stick. Verify your machine's OCV before use.\"}},\n    {\"@type\": \"Question\", \"name\": \"Is E7018 required for all structural welding?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Only when code specifies Low Hydrogen (AWS D1.1 Table 4.5 Category F), or when the joint is thick\/restrained\/high-yield, or when CVN toughness is required. For simple mild steel low-restraint work, E7014 or E6013 may be acceptable — verify with the applicable code.\"}},\n    {\"@type\": \"Question\", \"name\": \"Can IronArc 7018 MR be used for pipe root passes?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"E7018 can be used for root passes on ceramic-backed or back-gouged pipe configurations. For open-root pipe, most WPS call for E6010 root and hot pass, then E7018 fill and cap.\"}}\n  ]\n}\n\u003c\/script\u003e\n\u003ch2\u003eE7018 H4R Low-Hydrogen Welding Rod Technical Notes\u003c\/h2\u003e\n\u003cp\u003eThe E7018 H4R classification represents the most stringent hydrogen control available for standard-strength structural carbon steel welding. Diffusible hydrogen testing per AWS A4.3 measures the total hydrogen released from a weld metal sample immersed in mercury at 45°C for 72 hours — H4 means this total does not exceed 4 mL per 100g of weld metal deposited. For comparison, standard E7018 (non-H designated) can exceed 8 mL\/100g, and a moisture-absorbed E7018 can reach 16 mL\/100g or higher. Hydrogen-induced cold cracking (HICC), also called underbead cracking or delayed cracking, occurs when three conditions coincide: susceptible microstructure (hardened HAZ martensite), sufficient hydrogen, and applied or residual tensile stress. Removing any one of these three factors prevents HICC — preheat reduces the HAZ hardness by slowing cooling, H4R limits hydrogen, and proper joint design minimizes residual stress concentration. For structural engineers and welding engineers specifying filler metal for thick, high-restraint, or higher-strength-steel joints, H4R designation provides the hydrogen control margin needed to prevent HICC even when preheat or interpass control is less than perfect. Lincoln IronArc 7018 MR combines H4R with moisture-resistant (MR) flux to extend the practical field exposure window, making it the most field-practical way to maintain H4R compliance on construction sites and in maintenance environments.\u003c\/p\u003e","brand":"Lincoln Electric","offers":[{"title":"5\/32 in, 50 lb Easy Open Can","offer_id":44222936514711,"sku":"ED040002","price":233.08,"currency_code":"USD","in_stock":true},{"title":"3\/16 in, 10 lb Easy Open Can","offer_id":44222936547479,"sku":"ED040003","price":145.25,"currency_code":"USD","in_stock":true},{"title":"3\/32 in, 10 lb Easy Open Can","offer_id":44222935957655,"sku":"ED040000-1","price":154.8,"currency_code":"USD","in_stock":true},{"title":"3\/32 in, 50 lb Easy Open Can","offer_id":44222935990423,"sku":"ED040000","price":241.63,"currency_code":"USD","in_stock":true},{"title":"1\/8 in, 10 lb Easy Open Can","offer_id":44222936481943,"sku":"ED040001-1","price":151.56,"currency_code":"USD","in_stock":true},{"title":"1\/8 in, 50 lb Easy Open Can","offer_id":44222936023191,"sku":"ED040001","price":233.08,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0628\/7140\/4695\/files\/lincoln-ed040002-ironarc-7018-mr-stick-smaw-welding-rod-532x14-in-50-lb-easy-open-can-lincoln-electric-1.jpg?v=1746614844","url":"https:\/\/weldingmart.com\/products\/lincoln-ironarc-7018-mr-x-14-smaw-welding-rod","provider":"WeldingMart.com","version":"1.0","type":"link"}