Table 5.6 · खंड 7.2Mill Test Report (MTR) — How to Read One for D1.1 वेल्डिंग Compliance
A mill test report certifies the chemical composition and mechanical properties of a specific heat of steel. For D1.1:2025 compliance, the MTR connects your steel to Table 5.6 आधार धातु groups, which determine पूर्वतापन आवश्यकताएँ, भराव धातु selection, and whether your WPS can be prequalified.
The D1.1 connection: Your MTR shows the ASTM विनिर्देश. Table 5.6 maps that specification to a base metal group (I through V). The group determines your preheat per Table 5.11 and your filler metal per Table 5.7. Without the MTR, you cannot look up any of these requirements.
एक एमटीआर में क्या होता है
A mill test report is the steel producer’s certified record for a specific heat (batch) of steel. Every structural steel delivery should be accompanied by an MTR that traces back to the producing mill. The document typically contains the following information:
- हीट संख्या
- पिघले हुए स्टील के एक विशिष्ट बैच को मिल द्वारा सौंपा गया एक अद्वितीय पहचानकर्ता। हीट संख्या भौतिक स्टील और उसके प्रमाणित गुणों के बीच प्राथमिक पता लगाने योग्य लिंक है। एक ही हीट से प्रत्येक प्लेट, बीम, या आकार समान रसायन विज्ञान साझा करता है।
- ASTM विनिर्देश और ग्रेड
- The मानक the steel was produced to meet, such as ASTM A992, ASTM A572 Gr.50, or ASTM A36. This is the field that connects directly to D1.1
Table 5.6. If the specification and grade are listed inTable 5.6, the steel is approved for prequalified WPSs. - रासायनिक विश्लेषण
- हीट की वास्तविक रासायनिक संरचना, वजन प्रतिशत के रूप में रिपोर्ट की गई। मुख्य तत्वों में कार्बन (C), मैंगनीज (Mn), सिलिकॉन (Si), फास्फोरस (P), सल्फर (S), और कुछ ग्रेडों के लिए, क्रोमियम, निकल, मोलिब्डेनम, वैनेडियम, और तांबा शामिल हैं। इन मानों का उपयोग
Annex Bके अनुसार वैकल्पिक पूर्वतापन निर्धारण के लिए कार्बन समतुल्य की गणना के लिए किया जाता है। - Mechanical properties
- Test results from specimens pulled from the heat, including न्यूनतम yield शक्ति (ksi or MPa), tensile strength (ksi or MPa), elongation (percent), and in some cases Charpy V-notch impact values. These must meet the requirements of the ASTM specification listed on the MTR.
- उत्पाद आयाम और मात्रा
- रिपोर्ट द्वारा कवर की गई सामग्री का आकार, आकृति और मात्रा। एक एकल एमटीआर एक ही हीट से कई टुकड़ों को कवर कर सकता है।
From MTR to D1.1 Compliance: Three Steps
The entire purpose of reading an MTR for D1.1 compliance is to answer three questions: what group is my steel in, what preheat do I need, and which filler metals match? Here is the workflow:
Table 5.6
Take the ASTM specification and grade from your MTR and look it up in D1.1 Table 5.6. The तालिका lists approved base metals organized by group (I through V). For example, A992 appears in Group II. A36 appears in both Group I (for thicknesses up to 3/4 in) and Group II (all thicknesses). If your steel is not listed in Table 5.6, it is not approved for prequalified WPSs and must be qualified by परीक्षण per Clause 6.2.1 with a PQR.
Table 5.11
The base metal group from Table 5.6 determines which preheat श्रेणी applies in Table 5.11. The पूर्वतापन तापमान depends on three factors: the steel group, the वेल्डिंग प्रक्रिया category (which reflects hydrogen level), and the material मोटाई. Use the preheat calculator to look up the exact value for your combination.
Table 5.7
Table 5.7 specifies which filler metals provide matching strength for each base metal group. Group I and II steels use E60XX or E70XX electrodes for SMAW, and F6XX or F7XX fluxes for SAW. Higher groups require higher-strength filler metals. The filler metal must match or exceed the base metal strength to satisfy D1.1 requirements.
The Five Base Metal Groups
D1.1:2025 Table 5.6 organizes all approved base metals into five groups based on yield strength and alloy content. Understanding which group your steel belongs to is fundamental to every D1.1 decision that follows.
समूह I — माइल्ड स्टील (30–50 ksi यील्ड)
The most common structural steels for light-duty applications. Includes A36 (up to 3/4 in), A53, A500, A501, A1011 SS, and API 5L. These steels have the lowest preheat requirements and the widest range of approved filler metals. Most small fabrication shops work primarily with Group I steels.
Group II — Structural Steels (36–55 ksi yield)
The workhorse group for structural fabrication. Includes A992 (the standard wide-flange steel), A572 Gr.50, A588 weathering steel, A913 Gr.50, and A36 at all thicknesses. If you are fabricating a steel building frame in the United States, most of your steel is Group II. Preheat requirements are moderate and increase with thickness.
समूह III — उच्च-शक्ति वाले स्टील (55–65 ksi यील्ड)
Includes A572 Gr.60 and Gr.65, A633 Grade E, and A913 Gr.60 and Gr.65. These steels require higher preheat temperatures and more careful ऊष्मा इनपुट control. They are used in applications where higher strength reduces member sizes and overall structural weight.
समूह IV — उच्च-शक्ति वाले स्टील (70 ksi यील्ड)
Includes A709 HPS70W (high-performance steel for bridges), A913 Gr.70, and A1066 Gr.70. These steels require the highest preheat temperatures among the commonly used structural grades. Filler metal matching requires E80XX or higher electrodes.
समूह V — बहुत उच्च-शक्ति वाला स्टील (80 ksi यील्ड)
वर्तमान में A913 Gr.80 तक सीमित है। इस समूह में सबसे सख्त पूर्वतापन और ऊष्मा इनपुट आवश्यकताएँ हैं। Clause 7.7 की ऊष्मा इनपुट सीमाएँ Table 5.6 में एक फुटनोट के अनुसार A913 ग्रेडों पर लागू नहीं होती हैं, क्योंकि A913 एक नियंत्रित प्रक्रिया (शमन और स्व-टेम्परिंग) द्वारा निर्मित होता है जो इसे पारंपरिक शमन और टेम्पर किए गए स्टील्स की तुलना में अलग थर्मल प्रतिक्रिया विशेषताएँ देता है।
वेल्डिंग से पहले एमटीआर पर क्या जांचें
Before welding begins, the fabricator or QC personnel should सत्यापित करें the following items on the MTR against the contract document requirements:
- विनिर्देश अनुबंध दस्तावेज़ों से मेल खाता है
- The ASTM specification and grade on the MTR must match what the contract documents specify. If the contract calls for A992 and the MTR shows A36, the steel does not meet the specification regardless of whether its mechanical properties happen to be adequate.
- Yield and tensile strength meet minimums
- The actual test values on the MTR must meet or exceed the minimum requirements for the specified grade. For A992, minimum yield is 50 ksi and tensile range is 65–100 ksi. Values outside these ranges indicate the steel does not conform.
- रसायन विज्ञान सीमाओं के भीतर है
- प्रत्येक ASTM विनिर्देश मुख्य तत्वों के लिए अधिकतम (और कभी-कभी न्यूनतम) मानों को परिभाषित करता है। अत्यधिक कार्बन या मैंगनीज कठोरता और क्रैकिंग संवेदनशीलता को बढ़ा सकता है। रसायन विज्ञान मान D1.1
Annex Bमें वैकल्पिक पूर्वतापन निर्धारण के लिए उपयोग किए जाने वाले कार्बन समतुल्य गणना को भी फीड करते हैं। - हीट संख्या पता लगाने की क्षमता
- Every piece of steel should be traceable to a heat number on an MTR. If steel arrives without traceability, the fabricator cannot verify its specification, and D1.1 compliance cannot be demonstrated. Missing traceability is a red flag that should stop fabrication until resolved.
एमटीआर रसायन विज्ञान से कार्बन समतुल्य
The chemical analysis on an MTR provides all the values needed to calculate कार्बन समतुल्य using the D1.1 Annex B formula. Carbon equivalent is a single number that represents the overall alloy content of the steel and its susceptibility to hydrogen-induced cracking in the ताप प्रभावित क्षेत्र.
D1.1 Annex B CE(IIW) सूत्र का उपयोग करता है: CE = C + (Mn+Si)/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15। एक उच्च CE का अर्थ है कि स्टील अधिक कठोर है और मानक Table 5.11 मानों की तुलना में उच्च पूर्वतापन की आवश्यकता हो सकती है। Annex B CE, हाइड्रोजन स्तर, और संयम के आधार पर पूर्वतापन निर्धारित करने के लिए एक वैकल्पिक विधि प्रदान करता है — यह तब उपयोगी होता है जब मानक तालिका मान अत्यधिक रूढ़िवादी लगते हैं या जब समूह सीमाओं के पास के स्टील्स के साथ काम कर रहे हों।
Use the carbon equivalent calculator to compute CE(IIW) and Pcm directly from your MTR chemistry values.
"यदि एमटीआर WPS से मेल नहीं खाता है, तो वेल्डिंग बंद कर दें। सबसे महंगी मरम्मत वह है जो आप संरचना के लोड हो गया होने के बाद करते हैं।"
— Fabrication shop floor principle, consistent with D1.1:2025Table 5.6base metal requirements
अक्सर पूछे जाने वाले प्रश्न
In practice, yes. A mill test report (MTR), mill certificate (mill cert), and certified material test report (CMTR) all refer to the same document: the steel producer's certified record of chemical analysis and mechanical test results for a specific heat of steel. The terms are used interchangeably in the structural steel industry. EN 10204 uses the term inspection certificate, but the content is equivalent.
D1.1:2025 Clause 7.2.1 requires that contract documents designate the specification and classification of base metal. The code requires you to know what steel you are welding so you can apply the correct preheat, filler metal, and procedure. The MTR is the standard industry document that proves which specification applies. While D1.1 does not prescribe the document format, most contract documents and building codes require MTRs for structural steel traceability.
Table 5.6 organizes approved base metals into five groups based on strength and chemistry. Group I includes common mild steels like A36 and A500 with yield strengths of 30 to 50 ksi. Group II includes structural steels like A992, A572 Gr.50, and A588 with yield strengths of 36 to 55 ksi. Group III covers higher-strength steels like A572 Gr.60 and A913 Gr.60 at 55 to 65 ksi. Group IV includes A709 HPS70W and A913 Gr.70 at 70 ksi. Group V is A913 Gr.80 at 80 ksi yield.
Three steps. First, find the ASTM specification and grade on your MTR. Second, look up that specification in D1.1 Table 5.6 to find the base metal group (I through V). Third, use the group to look up the minimum preheat temperature in Table 5.11 based on your welding process category and material thickness. For example, A992 steel is Group II. For SMAW with low-hydrogen electrodes on 1 in thick plate, Table 5.11 Category B requires 50 degrees F minimum preheat.
Confirm the heat number, ASTM specification, grade, dimensions, chemistry, and mechanical test results all match the material delivered and the contract documents. If the MTR cannot be tied to the piece mark or heat number on the steel, the fabricator cannot prove the base metal group for D1.1 preheat, filler-metal selection, or WPS qualification.
Yes. The specification and grade on the MTR determine whether the steel is listed for prequalified D1.1 work. The chemistry can also reveal high carbon equivalent or alloy content that increases hydrogen-cracking risk. If the material is not covered by the prequalified base metal tables, the WPS must be qualified by testing instead of treated as a routine prequalified procedure.