QT vs annealed vs normalized steel bars

Separate heat-treatment condition from the bar's surface and product route

The buyer first needs to identify which state the drawing or process plan requires. Quenched and tempered (+QT), annealed (+A where the controlling standard uses that symbol), and normalized (+N) describe thermal histories. Hot rolled or forged describes how the bar was formed. Peeled, turned, ground, or rough machined describes material removed from the surface. A supplier can therefore offer a +QT peeled bar or an annealed hot-rolled bar without contradiction. An RFQ that asks for 'QT or peeled' is comparing different dimensions of the requirement.

QT is usually reviewed when the supplier is expected to deliver a defined strength-toughness condition before machining. Annealed supply can reduce hardness or improve a later machining, forming, or heat-treatment route, depending on grade and process. Normalizing can refine or homogenize a prior structure and can be a delivery condition where the product standard and design permit it. None of those descriptions proves the finished component's fatigue strength, case depth, induction response, distortion, or service suitability. The materials or design authority must choose the condition that fits the complete manufacturing route.

Create a simple state map before requesting prices: starting product form and size; condition at supplier testing; surface-removal stage; size entering buyer machining; any forging or final hardening; and finished-part acceptance. Mark which organization owns each operation. This exposes a frequent commercial mismatch: one bid includes production quench and temper with mechanical testing, while another supplies annealed stock for the buyer to heat treat. Their prices and lead times are not comparable until responsibilities and acceptance states align.

Sources:[1][2][3][4]

Keep chemistry, condition, section size, and property basis in the same standard row

The table is not a ranking of conditions. It shows why a complete route can carry standard values while a free-standing word such as annealed or normalized cannot. ISO +QT values are tied to a named designation, product scope, ruling-section band, and standard test basis. When the condition, diameter band, or product form changes, the buyer must select the applicable licensed table or agree another acceptance route rather than carrying over convenient numbers.

42CrMo4 and C45 illustrate the section effect. Both ISO routes reduce the stated minimum yield basis between the >16–40 mm and >40–100 mm round ruling-section bands. A small qualification coupon therefore cannot be assumed to represent the core of a larger bar. The order should define the ruling section used to select the band, the specimen's radial and longitudinal location, orientation, heat-treatment relationship, and whether the result represents a heat, heat-treatment lot, bar, or separately processed test piece.

Annealed and normalized orders need equal care even when no tensile acceptance is requested. Identify the exact condition symbol or wording allowed by the controlling product standard, plus any hardness maximum or range that genuinely applies to the ordered grade, size, and product form. If the standard does not supply the needed value for that route—or if the buyer only wants a process input—write the agreed incoming control explicitly. Do not copy a +QT tensile row onto annealed material or promise an undefined 'easy machining' result.

Values are condensed for RFQ screening. Verify the purchaser's licensed standard editions, designation, product form, heat and product analysis rules, exact delivery-condition symbol, ruling section, specimen location, orientation, test temperature, frequency, retest rules, dimensions, surface, and order options. Only accepted order terms define the requirements for a specific supply.

Sources:[1][2][3][4][5]

Sources:[1][2][3][4][5]

Choose the condition from the downstream process, not from a simple better-or-worse ladder

Supplier-delivered +QT bar can shorten the buyer's route when the ordered section and properties are achievable, the part will be machined without a later hardening cycle, and dimensional movement can be managed. It can also create higher machining loads, more sensitivity to local overheating or abusive straightening, and wasted heat-treatment cost if the buyer will reforge or fully re-austenitize the material. Ask which thermal operation is the final one governing the component properties. Earlier certificates become process-history evidence, not proof of the final state after a later transformation.

Annealed supply may be appropriate when the buyer needs lower incoming hardness, substantial machining, cold work, forming, or a controlled starting condition before final treatment. But annealed is not a single microstructure or machining guarantee across all grades and furnace routes. The RFQ should identify the accepted condition from the product standard, incoming hardness basis if required, decarburization allowance, structure or spheroidization requirement only where a controlled specification supports it, and the downstream operation that depends on the condition.

Normalized supply may be selected as a final standard condition for some components or as an intermediate structure before machining and later processing. Again, the word is not enough. A normalized C45 route should not silently inherit 42CrMo4 +QT mechanics, and normalized alloy bar should not be represented as equivalent to a strength-class QT order. If the drawing states only a property requirement, the supplier may propose a route, but the accepted order must still name the delivery condition and controls before manufacture.

Sources:[1][2][3][4]

Make testing, traceability, and release evidence represent the ordered state

A tensile method and a property requirement are different things. ISO 6892-1 defines room-temperature tensile testing, but it does not choose the grade values, specimen location, represented section, frequency, or acceptance rule for the order. Record whether specimens are longitudinal or transverse, their radial and end location, whether they come from the delivered bar or a prolongation, and which heat-treatment lot they represent. If the purchaser needs core evidence, say so; a convenient near-surface coupon should not become an accidental full-section guarantee.

Hardness can be an incoming process control, a correlation check, or a final acceptance requirement. State which role it plays, the method and scale, surface preparation, test location, frequency, range, averaging or individual-value rule, and disposition of nonconforming readings. Avoid acceptance by informal conversion between Brinell, Rockwell, and Vickers unless the order names an approved conversion basis and uncertainty. For annealed stock, a maximum hardness may protect machinability; for +QT stock, a range may support process consistency. Neither substitutes automatically for tensile or impact tests.

ISO 10474 defines types of inspection documents supplied according to the order. Naming a document type does not create tests that the product standard or PO never required. List the actual results that must appear: heat analysis, grade and standard edition, delivery and surface condition, heat-treatment lot, tensile and impact results when ordered, hardness, dimensions, straightness, surface findings, NDT if separately specified, and heat-to-bar or heat-to-bundle traceability. Define whether document review is informational, a witness point, or a shipment hold point.

Preserve identity through subcontracted processing. If heat treatment, peeling, grinding, or testing occurs outside the producing mill, ask who retains responsibility, how material and process-lot identities are reconciled, and which reports feed the final certificate. A certificate stating +QT without a link between tested lot and shipped bundles does not close the traceability question.

Sources:[1][2][5][6]

Turn the process decision into comparable quotation and order wording

Ask every bidder to return a compliance matrix against one required route. The matrix should identify the proposed standard and edition, grade, product form, delivery condition, surface condition, heat-treatment section, test representation, mechanical or hardness basis, dimensions, straightness, inspection document, actual reported results, subcontracted scope, packing, price basis, and lead time. Put alternatives in a separate schedule. A cheaper annealed offer is not a deviation-free substitute for +QT bar, and a +QT upgrade should not be accepted without checking whether the buyer's downstream route makes it unnecessary.

The worked line below deliberately uses bracketed project inputs. Procurement should obtain those values from the drawing and process owner instead of copying a generic web range. If the condition is genuinely open, ask the supplier to propose and justify one route, but state the final acceptance properties, authority for approval, and no-manufacture-before-approval rule. Resolve every condition or surface ambiguity before the PO acknowledgment.

At purchase-order review, check that the property row matches the actual ruling section and delivery state, that the inspection document reports the required results, and that later buyer processing is not described as supplier-certified performance. Freeze approved deviations and revision status in the PO. Only accepted order terms define the requirements for a specific supply.

Item: Alloy steel round bars for machined shaft blanks, drawing [number / revision], [quantity]
Grade / standard: 42CrMo4 to ISO 683-2:2016 [or purchaser-controlled adoption]; alternatives only in a clause-by-clause deviation schedule
Size: Ø[ordered diameter] × [length / tolerance]; ruling section [definition]; minimum clean-up diameter and machining allowance per drawing
Delivery condition: +QT [or +A / +N only when the controlling standard and process plan require it]; surface [hot rolled / peeled / rough machined]; supplier to declare straightening and stress-relief sequence
Mechanical properties: [applicable size-band values and any project additions], specimen orientation/location, heat-treatment representation, frequency and retest rule per attached schedule
Downstream processing: Buyer will [machine / forge / re-heat-treat / induction harden / grind]; supplier certificate applies only to the stated delivered condition
Inspection: Heat analysis, ordered mechanical/hardness results, dimensions, straightness, surface and marking; NDT only to the separately named method, coverage and acceptance
Certificate: ISO 10474 type [state type] with actual results, condition, heat, process-lot, specimen and bundle traceability
Supplier response: Identify included and subcontracted operations, proposed route, open inputs, exclusions, price/lead-time effects, and every deviation
Packing / destination: [preservation, supports, bundle limits, port, Incoterm]
Only accepted order terms define the requirements for a specific supply.

Sources:[1][2][3][4][5][6]