ISO 6336-5-2016 PDF

Full title and description

St ISO 6336-5-2016 — Calculation of load capacity of spur and helical gears — Part 5: Strength and quality of materials. This part specifies numerical values and requirements for material strength, heat treatment and quality that are used when rating contact (pitting) and tooth-root (bending) strength of gear teeth and when applying the calculation procedures of the ISO 6336 series and related gear-rating standards.

Abstract

ISO 6336-5:2016 describes contact and tooth-root stresses and gives numerical values for both limit stress numbers. It specifies material quality and heat‑treatment requirements and explains their influence on allowable and limit stress numbers. The values and procedures are intended for use with ISO 6336‑2, ISO 6336‑3, ISO 6336‑6 and related application standards and are consistent with ISO 10300 for bevel gears.

General information

• Status: Published — third edition (confirmed in a 5‑year review in 2022; remains current as of confirmation).
• Publication date: August 2016 (Edition 3, 2016).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.200 (Gears).
• Edition / version: Edition 3 (2016).
• Number of pages: 47 pages in the ISO published text (national/adopted publications such as the BSI national version may show differing page counts, e.g. 58 pages, owing to national forewords/annexes).

Scope

Specifies limit and allowable stress numbers for contact (pitting) and bending (tooth‑root) strength and gives the material quality and heat‑treatment requirements needed to achieve those values. It applies to spur and helical gears covered by the ISO 6336 series and is intended to be used together with the calculation procedures given in ISO 6336‑2, ISO 6336‑3, ISO 6336‑6 and ISO 10300 (bevel gears). The part defines reference test‑gear conditions and indicates the limits of applicability for the provided numerical values.

Key topics and requirements

• Definition and tabulation of nominal (limit) and allowable stress numbers for contact (σHlim) and bending (σFlim, σFE) based on test‑gear data and reference conditions.
• Requirements and classification of material quality (wrought steels, cast steels, cast irons, carburized and surface‑hardened steels, nitrided steels, etc.) and corresponding figures/tables for stress numbers.
• Guidance on heat treatment and surface hardening (case depth, hardness ranges, limits to avoid embrittlement) and recommended minimum/maximum hardness values for the tabulated stress numbers.
• Notes on reference test conditions (module, face width, centre distance, roughness, lubricant viscosity, velocity and accuracy grades) used to derive the presented values and the need to apply correction factors when real conditions differ.
• Instructions for calculating stress numbers from hardness and material constants (example formulae and A/B constants for different material categories).

Typical use and users

Used by gear designers, mechanical design engineers, gearbox manufacturers, metallurgists and standards committees to select materials, specify heat treatments, determine allowable stresses for strength calculations and to verify load ratings during design reviews, procurement and acceptance testing. It is also used by software developers implementing ISO gear‑rating calculations.

Related standards

Primary related documents are ISO 6336‑1 (general considerations), ISO 6336‑2 (pitting/ contact stress calculation), ISO 6336‑3 (bending strength), ISO 6336‑6 (litigations/working life and reliability factors), and ISO 10300 (bevel gear rating). Other related standards referenced include ISO 1328 (accuracy), ISO 53 (basic rack), and material/heat‑treatment standards referenced by ISO 6336‑5 for hardness and case‑depth specifications.

Keywords

gear rating, load capacity, contact stress, pitting, tooth‑root bending, material quality, heat treatment, case depth, hardness, ISO 6336, bevel gears, σHlim, σFlim.

FAQ

Q: What is this standard?

A: ISO 6336‑5:2016 is Part 5 of the ISO 6336 series and provides the strength parameters and material/heat‑treatment quality requirements used when calculating the load capacity (contact/pitting and bending) of spur and helical gears.

Q: What does it cover?

A: It covers the derivation and tabulation of nominal (limit) and allowable stress numbers for contact and bending, material categories and quality classes, recommended hardness and case‑depth ranges for different treatments, and guidance on how those values relate to the calculation procedures in other ISO gear‑rating parts.

Q: Who typically uses it?

A: Gear designers, gearbox manufacturers, mechanical engineers, materials and heat‑treatment specialists, test laboratories and software vendors implementing ISO gear rating methods.

Q: Is it current or superseded?

A: The 2016 third edition is the current ISO edition for Part 5; the ISO record shows the publication as Edition 3 (2016) and that it was reviewed and confirmed in 2022, so it remains current. (Earlier editions, e.g. 2003 and 1996 versions, have been withdrawn.)

Q: Is it part of a series?

A: Yes — ISO 6336 is a multi‑part standard for calculation of load capacity of spur and helical gears. Part 1 covers general principles; Parts 2 and 3 cover contact (pitting) and bending calculations respectively; Part 5 provides material strength and quality data; Part 6 and other parts address life and application‑specific factors.

Q: What are the key keywords?

A: Contact stress, pitting, bending (tooth‑root) stress, material quality, heat treatment, hardness, case depth, allowable stress numbers, ISO 6336.