TECHNICAL SELECTION GUIDE

Steel comparison centre

Compare chemistry, strength, hardenability, machining, welding and total process cost without reducing grades, manufacturing methods and tolerances to a single criterion.

Contents

11 COMPARISONS

Go to the comparison relevant to your decision

4140 / 42CrMo4 compared with C45 / CK45
4140 / 42CrMo4 compared with 4340 / 34CrNiMo6
ST52 / S355 compared with ST37 / S235
16MnCr5 compared with 20MnCr5
16MnCr5 / 1.7131 compared with AISI 8620
C45 / CK45 compared with ST52 / S355
ST37 / S235: hot-rolled compared with cold-drawn
C45 / CK45: hot-rolled compared with cold-drawn
ST52 / S355: hot-rolled compared with cold-drawn
Cold-drawn shafting compared with peeled steel bar
h9 compared with h11 shaft tolerances

Set the specification first“4140”, “ST52”, “shafting” or “h9” alone is not a complete purchasing description. Specify the standard, grade suffix, product form, dimensions, tolerances, surface, delivery condition, heat treatment, tests and 3.1 certificate requirements together.

COMPARISON 1

4140 / 42CrMo4 compared with C45 / CK45

Alloy content and hardenability are the main differences between these two engineering steels. C45 is an economical, machinable medium-carbon option; 42CrMo4 is selected for higher strength through the section with a suitable quenching and tempering process.

4140 / 42CrMo4 compared with C45 / CK45: technical preselection table
Criterion	4140 / 42CrMo4	C45 / CK45
Chemical composition	Approximate EN reference: C 0.38–0.45%; Cr 0.90–1.20%; Mo 0.15–0.30%.	Approximate EN reference: C 0.42–0.50%; Cr and Mo are not mandatory alloying elements.
Mechanical behaviour	High strength–toughness balance in the quenched and tempered condition; values vary with diameter and tempering temperature.	Medium to high strength in the normalised or quenched and tempered condition; consistency of properties is more limited in thick sections.
Hardenability	Higher and more consistent deeper into the section due to Cr-Mo alloying.	Hardens through its carbon content; effective hardening depth becomes more limited as section size increases.
Surface	The grade name does not define the surface; hot-rolled, peeled or ground supply can be specified.	The grade name does not define the surface; a hot-rolled or machined/bright form can be selected.
Tolerance	Depends on the bar manufacturing method and ordered standard; it cannot be inferred from the grade code.	Likewise defined by product standard, diameter and delivery form.
Welding	Requires preheating, controlled heat input and, where necessary, post-weld treatment; procedure approval is required.	The carbon equivalent demands care in welding; procedure and preheating must be assessed even for thin sections.
Machining	Machined soft-annealed or at a suitable hardness; quenched and tempered hardness affects tool selection.	Usually economical and predictable; delivery hardness and sulphur level affect the result.
Heat treatment	Quenching and tempering is the main route; induction surface hardening is also possible.	Normalising, quenching and tempering, or induction/flame surface hardening may be used.
Applications	Highly loaded shafts, gears, fasteners and machine parts.	Moderately loaded shafts, pins, bushes, dies and general machine parts.
Cost / process	Material/process cost is generally higher because of alloying and controlled heat treatment.	Material and processing costs are lower in many general manufacturing applications.
Selection caution	Select 42CrMo4 when load, fatigue, section size and target core hardness require it; do not substitute on name similarity alone.	C45 may be economical if it meets the design loads; do not use it in place of 4140 without certification and engineering calculations.

Sources and scope

Ovako Steel Navigator — 42CrMo4 Ovako Steel Navigator — C45

The ranges and characteristics in the table are for preselection. Binding values depend on the specified product standard, actual section, delivery/heat-treatment condition and EN 10204 3.1 certificate.

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Product and supply information: 4140 / 42CrMo4 · C45 / CK45.

COMPARISON 2

4140 / 42CrMo4 compared with 4340 / 34CrNiMo6

The nickel content and stronger alloy system of 34CrNiMo6 may offer advantages for large sections and high toughness requirements; the trade-off is material, heat-treatment and verification cost.

4140 / 42CrMo4 compared with 4340 / 34CrNiMo6: technical preselection table
Criterion	4140 / 42CrMo4	4340 / 34CrNiMo6
Chemical composition	EN reference for 42CrMo4, not a SAE 4140 acceptance table: C 0.38–0.45%; Cr 0.90–1.20%; Mo 0.15–0.30%.	EN reference for 34CrNiMo6, not a SAE 4340 analysis: C 0.30–0.38%; Cr 1.30–1.70%; Ni 1.30–1.70%; Mo 0.15–0.30%.
Mechanical behaviour	High strength and adequate toughness through quenching and tempering; the section effect must be checked in the certificate.	A strong candidate for large parts requiring high strength, high toughness and fatigue performance.
Hardenability	High; core properties in large sections must nevertheless be verified against the process.	Generally higher because of the Ni-Cr-Mo system; more uniform results are sought in large sections.
Surface	Depends on selection of a hot-rolled, forged, peeled or ground product.	Surface quality depends on the manufacturing route; the grade name alone is not a surface guarantee.
Tolerance	Depends on the ordered bar/forging standard and final machining.	The same applies; a higher alloy content is not a tolerance class.
Welding	Limited weldability; preheating and a procedure are required.	Weldable under certain conditions; hydrogen-cracking risk requires a more stringent procedure.
Machining	Manageable in a suitable annealed or quenched and tempered condition.	May become more difficult and increase tool costs as alloy content and hardness rise.
Heat treatment	Hardening and tempering; the treatment schedule depends on section and target hardness.	Hardening and tempering; temperature, holding time and cooling control are critical for large sections.
Applications	Shafts, gears, studs and highly loaded general machine parts.	Large axles, heavy machine parts, high-strength fasteners and fatigue-loaded parts.
Cost / process	Often advantageous because of widespread availability and lower alloy cost.	Generally more expensive because of Ni content, sourcing and process control.
Selection caution	Do not specify an unnecessarily higher grade if the calculated section properties are met.	Do not choose it merely because it is “stronger”; verify impact, fatigue, section and heat-treatment requirements.

Sources and scope

Ovako Steel Navigator — 42CrMo4 Ovako Steel Navigator — 34CrNiMo6

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Product and supply information: 4140 / 42CrMo4 · 4340 / 34CrNiMo6.

COMPARISON 3

ST52 / S355 compared with ST37 / S235

ST37 and ST52 are historical/trade names. Current orders must state the full S235 or S355 grade suffix, product standard, impact class and delivery condition.

ST52 / S355 compared with ST37 / S235: technical preselection table
Criterion	ST52 / S355 class	ST37 / S235 class
Chemical composition	Low-carbon structural steel; chemical limits depend on product standard, thickness and variant.	Low-carbon structural steel; the S235 subgrade and product standard define the limits.
Mechanical behaviour	Higher nominal yield-strength class; the minimum may decrease with increasing thickness under the standard.	Lower nominal yield-strength class, with high formability in many general structures.
Hardenability	Not a quenching and tempering steel; designed for weldability and structural performance.	Not a quenching and tempering steel; high through-section hardness by quenching is not the aim.
Surface	May be as-rolled, blasted, primed or machined; specify in the purchase requirements.	The same product forms are possible; a grade class is not a surface-roughness specification.
Tolerance	Depends on plate/section/bar standard and dimensions.	Depends on plate/section/bar standard and dimensions.
Welding	Generally good; preheating depends on thickness, CEV, hydrogen and restraint.	Generally good; an approved WPS and material certificate remain essential.
Machining	Higher strength may increase cutting forces; surface and residual stresses also matter.	Generally easy to machine; product condition affects the result.
Heat treatment	Normalised/normalising-rolled variants may be available; subsequent quenching and tempering is usually not the purpose.	Depends on delivery condition; this is not a class chosen for high hardness.
Applications	Highly loaded machine frames, structures and welded parts.	General structures, lightly to moderately loaded frames and welded fabrication.
Cost / process	Unit price and welding/forming requirements may be somewhat higher; section reduction may be possible.	Common and economical; a larger section may be needed for the same load.
Selection caution	“ST52” is insufficient: specify an impact class such as S355JR/J0/J2 and the standard.	“ST37” is insufficient: clearly define S235JR/J0/J2 and the product standard.

Sources and scope

Ovako Steel Navigator — S355J2 SSAB — S355J2+N Zero

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Product and supply information: ST52 / S355J2 · ST37 / S235JR.

COMPARISON 4

16MnCr5 compared with 20MnCr5

Both grades are used for carburised parts requiring a hard surface and tough core. The carbon/manganese-chromium balance of 20MnCr5 differs; the drawing standard and carburising result are decisive.

16MnCr5 compared with 20MnCr5: technical preselection table
Criterion	16MnCr5 / 1.7131	20MnCr5 / 1.7147
Chemical composition	Approximate EN reference: C 0.14–0.19%; Mn 1.00–1.30%; Cr 0.80–1.10%.	Approximate EN reference: C 0.17–0.22%; Mn and Cr ranges are typically higher than for 16MnCr5.
Mechanical behaviour	A wear-resistant surface and ductile core are sought after carburising and hardening.	Similar function; core strength and hardenability differ with part section and process.
Hardenability	Moderate; common for carburised parts with small to medium sections.	Generally somewhat higher; may be considered for heavier sections or higher core-strength requirements.
Surface	Define the delivery surface and finish-grinding allowance after carburising separately.	The same applies; account for heat-treatment distortion in final dimensions and surface.
Tolerance	Plan tolerances and machining allowances before and after heat treatment.	The same planning is required because of heat-treatment distortion.
Welding	Primarily used for carburised parts; welding may disrupt the heat-treatment cycle and requires a special procedure.	Welding is generally not the design's main joining method; procedure assessment is required.
Machining	Machined in the soft-annealed or ferritic-pearlitic condition, then carburised.	Similar route; delivery hardness and machinability variant affect tool life.
Heat treatment	Carburising, quenching and low-temperature tempering; specify case depth on the drawing.	Carburising + quenching + low-temperature tempering; verify the treatment schedule and hardness profile with the producer.
Applications	Gears, pinions, cams, bushes and small to medium wear-loaded machine elements.	Gears, shafts, pinions and carburised parts that may require higher core strength.
Cost / process	A common and economical carburising option.	A small cost difference may arise from sourcing and process requirements; heat treatment determines overall cost.
Selection caution	Specify effective case depth and core strength, not surface hardness alone.	Do not automatically substitute for 16MnCr5; check analysis, Jominy band, section and drawing requirements.

Sources and scope

Ovako Steel Navigator — 16MnCr5 Ovako Steel Navigator — 20MnCr5

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Product and supply information: 16MnCr5 · 20MnCr5.

COMPARISON 5

16MnCr5 / 1.7131 compared with AISI 8620

Although the two materials serve a similar function, they are not exact standard equivalents. The Ni-Mo content of 8620 may change core toughness, hardenability and process response.

16MnCr5 / 1.7131 compared with AISI 8620: technical preselection table
Criterion	16MnCr5 / 1.7131	AISI/SAE 8620 ≈ 20NiCrMo2-2
Chemical composition	Approximately C 0.14–0.19%; Mn 1.00–1.30%; Cr 0.80–1.10%; Ni/Mo are not mandatory.	20NiCrMo2-2 +H, EN ISO 683-3 reference: C 0.17–0.23%; Mn 0.65–0.95%; Cr 0.35–0.70%; Ni 0.40–0.70%; Mo 0.15–0.25%.
Mechanical behaviour	Hard surface/tough core after carburising and hardening; the result depends on section and process.	Ni-Mo additions may benefit core behaviour in highly stressed transmission and bearing-type parts.
Hardenability	Moderate; an EN +H band can be requested separately in the order.	The Ni-Cr-Mo alloy system differs; compare the relevant +H / 8620H Jominy bands, section and process conditions.
Surface	Specify the machined surface and the ground surface after carburising separately.	The same applies; a grade code guarantees neither surface roughness nor tolerance.
Tolerance	Plan pre-machining allowance, distortion and final grinding tolerance.	The same applies; determine the heat-treatment route against the drawing tolerance.
Welding	Welding requires a specialist procedure coordinated with the carburising route.	The alloy system and carbon equivalent require welding/process engineering assessment.
Machining	Machined in the annealed/FP condition; an M-treated variant may be available.	Sulphur-controlled machinability variants may be available; check the certificate and delivery condition.
Heat treatment	The typical route is carburising, quenching and low-temperature tempering.	The same basic route; carbon potential and the hardening/tempering window require a different treatment schedule.
Applications	Gears, cams, pins and bushes.	Highly stressed gears and transmission elements, bearing/drivetrain parts.
Cost / process	Generally more economical as a common EN option without Ni-Mo additions.	Ni-Mo content and special grade requirements may increase material/sourcing cost.
Selection caution	For a drawing calling for 8620, specifying 1.7131 requires customer approval and a technical equivalence review first.	In place of 1.7131, use 8620 only after jointly approving chemistry, hardenability, hardness profile and standard.

Sources and scope

Ovako Steel Navigator — 16MnCr5 Ovako Steel Navigator — 20NiCrMo2-2

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Product and supply information: 16MnCr5 · AISI 8620 equivalents and standard notes — Turkish.

COMPARISON 6

C45 / CK45 compared with ST52 / S355

C45 is selected for heat treatment and machine-element performance; S355 for welded structural strength. Similar tensile values may occur, but their design purposes differ.

C45 / CK45 compared with ST52 / S355: technical preselection table
Criterion	C45 / CK45	ST52 / S355 class
Chemical composition	Medium carbon: approximately C 0.42–0.50%; unalloyed engineering steel.	Low-carbon/microalloyed structural steel; chemistry depends on product standard and thickness.
Mechanical behaviour	Hardness and strength can be adjusted by heat treatment; impact behaviour/toughness are affected by delivery condition.	Defined structural yield-strength class and weldability; the minimum depends on thickness.
Hardenability	Moderate; suitable for induction surface hardening.	Not a primary grade for quenching and tempering or surface hardening.
Surface	May be hot-rolled, peeled, cold-drawn or ground.	Plate/section/bar surface depends on the product standard.
Tolerance	Tight h tolerances are possible for bright bar and must be ordered separately.	Structural-product tolerance is defined by the product-form standard.
Welding	High carbon equivalent requires preheating and a tightly controlled procedure.	Generally better; WPS, thickness and CEV still require checking.
Machining	Common for machine elements; delivery hardness affects the result.	Machinable, but its principal advantage is welded construction.
Heat treatment	Normalising, quenching and tempering, induction/flame hardening.	Delivery condition may be +AR/+N; quenching and tempering for high hardness is not the typical choice.
Applications	Machined parts such as shafts, pins, bushes and gears.	Welded frames, load-bearing elements and general structures.
Cost / process	Machining and heat treatment determine total cost.	Economical in welded fabrication; machining allowance and product form matter.
Selection caution	Do not replace S355 merely for higher carbon content; welding and impact requirements are critical.	Do not select it instead of C45 based only on yield class; it may not meet hardness and wear requirements.

Sources and scope

Ovako Steel Navigator — C45 Ovako Steel Navigator — S355J2 SSAB — S355J2+N Zero

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Product and supply information: C45 / CK45 · ST52 / S355J2.

COMPARISON 7

ST37 / S235: hot-rolled compared with cold-drawn

The same base grade can have different surface, tolerance and mechanical behaviour because of its forming route. Check the delivery condition and mechanical certificate of cold-drawn products particularly carefully.

ST37 / S235: hot-rolled compared with cold-drawn — technical preselection table
Criterion	ST37 / S235 hot-rolled	ST37 / S235 cold-drawn
Chemical composition	S235/ST37 chemistry depends on grade/product standard; hot rolling does not change the chemistry.	The same heat chemistry is retained; cold drawing does not alter chemical composition.
Mechanical behaviour	A tendency towards higher ductility and lower yield/tensile strength.	Work hardening may increase yield/tensile strength and reduce elongation; no fixed universal value applies.
Hardenability	High hardenability is not the target; hardenability concerns chemistry, grain structure and heat treatment, not the manufacturing route alone.	Cold work hardening is not quench hardenability; do not confuse a high strength value with that concept.
Surface	Mill scale and a rougher surface may be present; cleaning/peeling is requested separately.	Smoother, brighter surface; drawing marks and straightening effects must be checked.
Tolerance	Wider rolling tolerance; depends on product standard and dimensions.	Tighter h tolerances are possible; state the exact class in the order.
Welding	Assess WPS/preheating against the grade's carbon equivalent and section.	The same chemical weldability applies; cold deformation and residual stresses must also be considered.
Machining	More surface cleaning and machining allowance may be needed.	Dimensional precision may reduce machining; the work-hardened layer can affect tool load.
Heat treatment	Account for initial microstructure and delivery condition in the treatment schedule.	Account for the cold-drawing effect in stress-relief and subsequent heat-treatment planning.
Applications	Structures, general fabrication and welded parts.	Shafting, pins, precision sections and series machining.
Cost / process	Unit material cost is generally lower; additional chip removal and finishing costs may follow.	Material/drawing cost may be higher; reduced machining allowance and series production offer advantages.
Selection caution	Hot rolling may be economical if surface and precise diameter are not critical; check drawing tolerances.	Do not automatically regard cold-drawn product as “better”; verify ductility, residual stresses and straightening effects.

Sources and scope

This comparison is governed by the product standard and supply certificate; check the current licensed ISO 286 standard for tolerance values.

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Product and supply information: ST37 / S235JR.

COMPARISON 8

C45 / CK45: hot-rolled compared with cold-drawn

Cold drawing C45 improves dimensions and surface while also changing mechanical properties and residual stresses. Plan subsequent quenching and tempering or induction treatment for the delivery condition.

C45 / CK45: hot-rolled compared with cold-drawn — technical preselection table
Criterion	C45 hot-rolled	C45 cold-drawn
Chemical composition	C45 chemistry depends on grade/product standard; hot rolling does not change the chemistry.	The same heat chemistry is retained; cold drawing does not alter chemical composition.
Mechanical behaviour	Medium-carbon steel behaviour depending on delivery condition and section.	Work hardening may increase strength and reduce elongation; monitor deformation after straightening/machining.
Hardenability	Moderate; core hardening may be limited as section size increases; hardenability concerns chemistry, grain structure and heat treatment, not the manufacturing route alone.	Cold work hardening is not quench hardenability; do not confuse a high strength value with that concept.
Surface	Mill scale and a rougher surface may be present; cleaning/peeling is requested separately.	Smoother, brighter surface; drawing marks and straightening effects must be checked.
Tolerance	Wider rolling tolerance; depends on product standard and dimensions.	Tighter h tolerances are possible; state the exact class in the order.
Welding	Assess WPS/preheating against the grade's carbon equivalent and section.	The same chemical weldability applies; cold deformation and residual stresses must also be considered.
Machining	More surface cleaning and machining allowance may be needed.	Dimensional precision may reduce machining; the work-hardened layer can affect tool load.
Heat treatment	Account for initial microstructure and delivery condition in the treatment schedule.	Account for the cold-drawing effect in stress-relief and subsequent heat-treatment planning.
Applications	Feedstock for forging/machining and general machine parts.	Precision shafts, pins and series parts with low machining allowance.
Cost / process	Unit material cost is generally lower; additional chip removal and finishing costs may follow.	Material/drawing cost may be higher; reduced machining allowance and series production offer advantages.
Selection caution	Hot rolling may be economical if surface and precise diameter are not critical; check drawing tolerances.	Do not automatically regard cold-drawn product as “better”; verify ductility, residual stresses and straightening effects.

Sources and scope

Ovako Steel Navigator — C45

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Product and supply information: C45 / CK45.

COMPARISON 9

ST52 / S355: hot-rolled compared with cold-drawn

Do not read S355 structural-class properties and the properties of cold-drawn bright bar as the same table. Match product standard, delivery condition such as +C, and section to the certificate.

ST52 / S355: hot-rolled compared with cold-drawn — technical preselection table
Criterion	S355 / ST52 hot-rolled	S355 / ST52 cold-drawn
Chemical composition	S355/ST52 chemistry depends on grade/product standard; hot rolling does not change the chemistry.	The same heat chemistry is retained; cold drawing does not alter chemical composition.
Mechanical behaviour	The section-dependent minima in the structural standard apply.	Cold forming may increase yield strength and reduce elongation; base S355 plate values do not transfer directly.
Hardenability	Not designed for quenching and tempering; structural strength and weldability are the targets; hardenability concerns chemistry, grain structure and heat treatment, not the manufacturing route alone.	Cold work hardening is not quench hardenability; do not confuse a high strength value with that concept.
Surface	Mill scale and a rougher surface may be present; cleaning/peeling is requested separately.	Smoother, brighter surface; drawing marks and straightening effects must be checked.
Tolerance	Wider rolling tolerance; depends on product standard and dimensions.	Tighter h tolerances are possible; state the exact class in the order.
Welding	Assess WPS/preheating against the grade's carbon equivalent and section.	The same chemical weldability applies; cold deformation and residual stresses must also be considered.
Machining	More surface cleaning and machining allowance may be needed.	Dimensional precision may reduce machining; the work-hardened layer can affect tool load.
Heat treatment	Account for initial microstructure and delivery condition in the treatment schedule.	Account for the cold-drawing effect in stress-relief and subsequent heat-treatment planning.
Applications	Frames, structures and welded machine bodies.	Precision square/hexagonal/round-section machine parts.
Cost / process	Unit material cost is generally lower; additional chip removal and finishing costs may follow.	Material/drawing cost may be higher; reduced machining allowance and series production offer advantages.
Selection caution	Hot rolling may be economical if surface and precise diameter are not critical; check drawing tolerances.	Do not automatically regard cold-drawn product as “better”; verify ductility, residual stresses and straightening effects.

Sources and scope

Ovako Steel Navigator — S355J2 SSAB — S355J2+N Zero

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Product and supply information: ST52 / S355J2.

COMPARISON 10

Cold-drawn shafting compared with peeled steel bar

These are manufacturing and surface-preparation descriptions, not grades. The same chemical grade may be supplied by two different routes; final selection depends on tolerance, surface, residual stress and subsequent processing.

Cold-drawn shafting compared with peeled steel bar: technical preselection table
Criterion	Cold-drawn shafting	Peeled steel bar
Chemical composition	May be SAE 1018/1020, C45 or another grade; “shafting” is not a chemical designation.	May be C45, 42CrMo4, S355, etc.; peeling does not define the chemistry.
Mechanical behaviour	Cold work hardening may increase strength and reduce ductility.	The surface is removed by machining; it does not aim for the degree of work hardening in cold drawing, and the base delivery condition is retained.
Hardenability	Depends on the selected steel grade; the process alone does not impart hardenability.	Depends on the selected steel grade and its heat treatment.
Surface	Bright/smooth; drawing and straightening marks may occur.	Clean metal surface with mill scale removed; longitudinal peeling marks may occur.
Tolerance	Common in tight tolerances such as h9–h11; specify the actual class in the order.	Improved compared with hot rolling; specify tolerance by producer/standard and do not confuse it with ground shafting.
Welding	Assess grade and cold-work effects together; welding changes the mechanical condition locally.	Chemical grade is decisive; surface cleanliness may help but does not remove the need for a WPS.
Machining	Accurate dimensions reduce chip removal; a work-hardened surface may affect cutting conditions.	The surface layer has been machined away; define acceptance criteria for remaining defects separately. A uniform starting surface may benefit large-diameter machining.
Heat treatment	Plan stress relief and machining sequence around residual stresses.	Apply heat treatment appropriate to the grade; plan allowance and distortion before/after peeling.
Applications	Pins, shafts, connections and precision series parts.	Large-diameter shafts, piston-rod feedstock and high-quality bar for machining.
Cost / process	Drawing and straightening costs may be offset by low machining allowance.	Peeling cost may be offset by surface-defect removal and machining efficiency.
Selection caution	Do not order by “shafting” alone; specify grade, tolerance, straightness and certificate.	Do not confuse peeled with ground; state Ra, diameter tolerance, straightness and surface-defect acceptance separately.

Sources and scope

This comparison is governed by the product standard and supply certificate; check the current licensed ISO 286 standard for tolerance values.

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Related guides: Cold-drawn shafting · Peeled steel bar — Turkish.

COMPARISON 11

h9 compared with h11 shaft tolerances

The lowercase h in ISO 286 denotes a shaft tolerance zone: upper deviation is zero and the zone lies below the nominal dimension. IT9 is narrower than IT11; the actual micrometre value varies with the nominal diameter range.

h9 compared with h11 shaft tolerances: technical preselection table
Criterion	h9 tolerance	h11 tolerance
Chemical composition	Tolerance does not alter chemistry; specify the selected grade separately.	Tolerance does not alter chemistry; specify the selected grade separately.
Mechanical behaviour	For the same material/delivery condition, h9 is not a mechanical property.	For the same material/delivery condition, h11 is not a mechanical property.
Hardenability	Depends on grade and heat treatment, independently of tolerance grade.	Depends on grade and heat treatment, independently of tolerance grade.
Surface	Tight tolerance usually accompanies a more controlled process; specify Ra separately.	Wider tolerance does not guarantee surface roughness; specify Ra separately.
Tolerance	Narrower IT9 zone. Example: in ISO 286, the >18–30 mm nominal range has approximately 0/−0.052 mm limits.	Wider IT11 zone. For the same >18–30 mm example range, approximately 0/−0.130 mm.
Welding	Welding may disrupt tolerance; plan finishing and straightening after welding.	Welding may disrupt tolerance; checks are required even with a wider assembly allowance.
Machining	Less dimensional variation and, in some applications, less finishing; tighter control adds cost.	Finishing/allowance requirements may rise; economical for rough or clearance assemblies.
Heat treatment	Heat-treatment distortion may violate h9; verification after final grinding/drawing is often required.	Allows more room for distortion; final measurement is still essential.
Applications	Precision bearing locations, bushes, coupling pre-dimensions and series shaft parts.	Connections allowing greater clearance and feedstock for rough machining.
Cost / process	Generally more expensive because of tighter process control and measurement.	Production with a wider tolerance may be more economical.
Selection caution	h9 alone does not define a fit type; specify hole tolerance, surface, straightness and operating clearance together.	Do not automatically use h11 for a precision bearing surface; calculate functional clearance and finishing allowance.

Sources and scope

This comparison is governed by the product standard and supply certificate; check the current licensed ISO 286 standard for tolerance values.

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TECHNICAL VERIFICATION

Confirm the selection against the drawing and certificate

Share load, section, impact temperature, fatigue, welding, target hardness profile and fit details; stock and cutting options are assessed against these inputs.

Request a technical quotation Open the grade finder

Technical sources and scope

Producer information is limited to the stated grade, product form and delivery condition; it is not automatic equivalence or confirmation of Erkal stock. Standard summaries do not replace the full standard. Sources checked: 11 September 2026.

Lucefin C45E — 2012 archive, designation reference

Salzgitter — S235JR1.0038

Ovako — Process, tolerance and surface roughness are separate order specifications

MISUMI — Published h9 limits within 1–200 mm match the current table

Rodacciai — Producer table: h shaft upper deviation zero, h11 widths 0.060 mm for 1–3 mm and 0.075 mm for over 3–6 mm