---
title: "Mill Test Report: What Steel Buyers Expect With Every Order"
url: https://www.uncap.com/post/mill-test-reports-steel-distributors
author: "Denis Dyli"
published: 2026-10-08
updated: 2026-10-08
summary: "A mill test report is the producing mill's certified record for a heat of steel, covering chemistry, tensile results, specification and grade. South Carolina DOT requires the report for each heat in a rebar delivery, and North Carolina DOT requires a Type 1 report tested on the same heat or lot shipped. Some US rebar producers state their reports meet EN 10204 type 3.1. On Shopify, Uncap builds the per-heat report onto the order during implementation."
---

# Mill Test Report: What Steel Buyers Expect With Every Order

> A mill test report is the producing mill's certified record for a heat of steel, covering chemistry, tensile results, specification and grade. South Carolina DOT requires the report for each heat in a rebar delivery, and North Carolina DOT requires a Type 1 report tested on the same heat or lot shipped. Some US rebar producers state their reports meet EN 10204 type 3.1. On Shopify, Uncap builds the per-heat report onto the order during implementation.

The inspector on the deck reads the heat number off the bundle tag and asks for the mill test report that matches it. Your yard shipped that steel Tuesday. The report sits in an email thread from the mill, and the pour is booked for morning.

Here is what the report holds, how to read it, and what buyers expect next to their order.

**Quick answer:** A mill test report (MTR) is the producing mill's certified record for a heat of steel: its chemistry, mechanical test results and the specification it meets. Buyers expect one for each heat in a delivery, matched to the tag, plus a domestic melt and manufacture statement when the owner requires it.

## What is a mill test report?

A mill test report is the steel producer's certified document tying a heat of steel to its test results. The Concrete Reinforcing Steel Institute (CRSI) says mill reports certify "that the reinforcing bar conforms to the project specifications" and reveal its chemical composition and mechanical properties. Texas DOT writes it as "The Mill Test Report (MTR)".

CRSI notes that certified mill test reports "typically accompany each shipment of reinforcing bars." The mill stands behind the numbers: Gerdau's rebar certification letter says the results on its Certified Mill Test Reports "are actual test results obtained on samples of the steel heats."

ArcelorMittal's sections mill calls its document a material test certificate, or MTC, and CMC refers to CMTRs. Whatever the title, a buyer asks three things: is this my steel, does it meet my spec, and can I use it on this job? Your job as a distributor or fabricator is getting the right report to the right buyer before anyone asks twice.

## How to read a mill test report, including the Buy America line

South Carolina DOT's [reinforcing steel supplemental specification](https://www.scdot.org/business/technicalPDFs/supSpecs/Section703-ReinforcingSteel-FHWA-Approved.pdf) lists what the mill test report must include: producer information, heat number and size, grade, tensile results and a domestic origin statement. Read those fields, plus the specification and chemistry the mill reports, against the order:

- Producer information. The mill that made the steel.
- Heat number and size. Match both to the tag on the bundle you shipped.
- Specification and grade. ASTM A615 covers "deformed and plain carbon-steel bars in cut lengths and coils for concrete reinforcement" in Grades 40, 60, 80 and 100. North Carolina DOT calls for A615, Grade 60 on its reinforcing steel.
- Chemistry. ASTM's A615 summary names carbon, manganese, phosphorus and sulfur.
- Tensile results. SCDOT wants "yield strength, tensile strength and elongation."
- Origin statement. SCDOT requires a "Statement ensuring that the steel was melted and manufactured in the United States."

That last line is the Buy America proof. On federal-aid highway work, paragraph (b)(1)(ii) of [23 CFR 635.410](https://www.ecfr.gov/current/title-23/chapter-I/subchapter-G/part-635/subpart-D/section-635.410) states that "if iron or steel products are to be used, all manufacturing processes, including application of a coating, for these materials must occur in the United States." North Carolina DOT's Type 1 report requirement carries the words "(Melted and Manufactured in the U.S.A.)", and Texas DOT says "Mill Test Reports should state that the materials were manufactured domestically." Whether a job is covered is a contract question, and your quality lead and the owner decide whether a heat qualifies.

Catch a mismatch at receiving, not on the deck.

## Heat numbers: why every delivery needs the matching report

The heat number ties a bundle back to the samples the mill tested. ASTM's A615 summary says steel samples "shall be rolled from properly identified heats." So owners count reports per heat, not per order. SCDOT says each rebar shipment "must be accompanied by the manufacturer's mill test report for each heat included in the delivery." Three heats on the truck means three reports.

North Carolina DOT's 2012 Standard Specifications separate a Type 1 certified mill test report, tested "on samples taken from the same heat or lot number as the material actually shipped," from a Type 2 typical report on a lot "that may or may not be from the lot shipped." Its [April 2025 concrete reinforcement guidance](https://connect.ncdot.gov/resources/Materials/MaterialsResources/Concrete_Reinforcement_Memo.pdf) says "ALL shipments of reinforcing steel must include a NCDOT Type 1 certified mill test report."

Its Form 913 has the fabricator list heat numbers by bar list or order number, bar mark, size and grade, "such that each heat number involved may be positively identified and separated, if necessary, at the destination." If your order system cannot say which heats went on which truck, someone rebuilds it by hand.

## Mill test certificate types under EN 10204: 2.1, 2.2, 3.1 and 3.2

EN 10204 is the European standard behind the 3.1 and 3.2 labels on mill test certificates. It covers inspection documents "supplied to the purchaser, in accordance with the requirements of the order, for the delivery of all metallic products."

- Type 2.1. The manufacturer declares compliance with the order, "without inclusion of test results."
- Type 2.2. The same, with results "based on non-specific inspection," where "the products inspected are not necessarily the products actually supplied."
- Type 3.1. ArcelorMittal's sections mill calls its ASTM A6 certificate a "type 3.1 EN10204 certificate of specific inspection," with results "for the same heat No. of the delivered materials." CMC says its certified mill test reports "are EN10204:2004 3.1 compliant."
- Type 3.2. The 2004 foreword says it replaced the earlier types 3.1.A and 3.1.C and the old inspection report 3.2.

Who must validate a 3.2 is set in the standard, so check that clause with the specifier before you promise one. Whether the page says mill test certificate or material test report, the question stays the same: do the results belong to the heat on the truck?

## What steel buyers expect when they order online

A contractor ordering rebar online expects the paperwork where the order is: open the order, see which heats shipped, download the report for each.

Uncap's [rebar and structural steel ecommerce page](https://www.uncap.com/industry/rebar-structural-steel) describes that build. On Shopify, attaching the mill test report for each heat on a delivery to that order, so the contractor and the inspector can pull it from order history, is built during implementation, and each order records which heat it ships from. The page is plain that heat-to-delivery document tracking is not in Uncap's published products; it is built from your ERP data, and the ERP stays the system of record. [Uncap Connect](https://www.uncap.com/products/connect) keeps Shopify in step, so inventory, orders, customers and pricing move the moment they change.

Running a contractor counter too? See [construction supply ecommerce](https://www.uncap.com/industry/construction-supply) for branch stock and job accounts, and our notes on [quote-to-order for construction supply](https://www.uncap.com/post/quote-to-order-construction-supply).

Uncap has been a Shopify Platinum Partner since 2013, with 380+ storefronts launched on Shopify. Talk to Our Experts, and bring the mill test reports from a recent delivery.

## Frequently asked questions

### What is a mill certificate for steel?

A mill certificate is the producer's certified record of test results for a heat of steel, issued under different names. ArcelorMittal's sections mill calls its document a material test certificate, and South Carolina DOT calls it the manufacturer's mill test report, which must show the heat number, grade and tensile results.

### What does MTR stand for in construction?

MTR stands for mill test report, the steel producer's certified test record for a heat of steel. Texas DOT uses the abbreviation in its Buy America documentation rules.

### How do you read a mill test report?

Read it against the order: match the heat number and size to the bundle tag, then check the specification, grade, chemistry and tensile results. South Carolina DOT also requires producer information and a domestic melt and manufacture statement.

### What is the difference between a mill test certificate and a material test certificate?

The label matters less than whose results the document carries and for which heat. North Carolina DOT separates a Type 1 certified mill test report on the heat or lot shipped from a Type 2 typical report that may not be from the lot shipped.

### Does every rebar delivery need its own mill test report?

On DOT jobs such as South Carolina's, yes, one for each heat in the delivery. South Carolina DOT requires the manufacturer's report for each heat included in a delivery. On private work, the project specification sets the rule.