This document provides information on UGIMA® 4305HM, an improved machinability austenitic stainless steel. It includes the chemical composition, standards, mechanical properties, physical properties, corrosion resistance, machinability, welding, heat treatment, forging, and available product forms. Although UGIMA takes care to verify the information, it cannot guarantee exactness and refuses responsibility for the data.

1. UGIMA®
4305HM
Chemical Analysis
C Si Mn Ni Cr Cu Mo Nb P S
≤0.07 ≤0.75 1,5-2 8.2 – 9.5 17.0 - 18.0 ≤0.75 ≤0,5  5xC - < 0.45.  0.040 0.25-0.35
07-09-2011 – REV05
Although UGITECH takes special care to verify the exactitude of the information printed. here, it cannot guarantee that this information is exact, reliable complete and reproducible as such by its customers.
UGITECH refuses all responsibility for the data indicate above and invites you to contact its Technical Assistance Department for a specific study of your needs.
General
presentation
UGIMA
®
4305 HM is an improved machinability stainless steel manufactured only by UGITECH.
Its properties are identical to those of 4305 except for its machinability, which is even better
than that of 4305:
 UGIMA
®
4305 HM is the first stainless steel produced by the new method of inclusion
population development and control, UGIMA
®
2, perfected by UGITECH.
 UGIMA
®
4305 HM's new technological advances are extremely advantageous, whatever the
machining conditions, machine or tooling used.
 Productivity increases of 50% over grade 4305, the current market standard, have been
obtained. A comparison with our UGIMA
®
4305, indicated a 25% increase in productivity.
Classification Improved Machinability Austenitic Stainless Steel.
Designation
N° Material
Europe USA Japan
EN ASTM JIS ISO (ISO15510)
1.4305
X8CrNiS18-9
UNS S30300 SUS303 4305-303-00-I
X10CrNiS18-9
Autre Désignation Matière
USA France Germay UK Sweden
AISI AFNOR DIN BS S.S
303 Z8CNF 18-09 1.4305 303S31 2346
UGIMA
®
4305 HM is supplied according to the following standards :
 EN 10088-3
 ASTM A581/581M - ASTM A582/582M
 AMS 5640 – type 1
 QQS 764 - SAE J405
 JIS G 4303 - JIS G 4308
Mechanical
properties Rp0,2% Rm A Z
(°C) (MPa) (MPa) (%) (%)
Without work hardening 250 / 350 570 / 650 65 /50 75 / 60
Work-hardened by drawing 360 / 670 685 / 850 47 / 26 56 / 37
(Average values for information only.)
Non-hardenable by heat treatment. Increased tensile strength and hardness is obtained by cold
working.
Physical
properties
Density
Module of
elasticity
Thermal
conductivity
Expansion coefficient
Electrical
resistivity
at 20°C
(kg/dm3) (N/mm2) (W/m.°C) at 20°C ( /°C) between 20°C and 200°C (µΩ.mm²)
7,9 196 000 15.3 W/m°C 16.8 x 10-6 cm/cm/°C 730
Weight of round bars Weight of hexagonal bars (young) Weight of square bars
0.0062 x D2
(D: mm)
0.0068 x D2
(D: mm)
0.0078 x c2
(for information only)

2. UGIMA®
4305HM
Chemical Analysis
C Si Mn Ni Cr Cu Mo Nb P S
≤0.07 ≤0.75 1,5-2 8.2 – 9.5 17.0 - 18.0 ≤0.75 ≤0,5  5xC - < 0.45.  0.040 0.25-0.35
07-09-2011 – REV05
Avenue Paul Girod
73403 UGINE Cedex - France
www.ugitech.com
2
Although UGITECH takes special care to verify the exactitude of the information printed. here, it cannot guarantee that this information is exact, reliable complete and reproducible as such by its customers.
UGITECH refuses all responsibility for the data indicate above and invites you to contact its Technical Assistance Department for a specific study of your needs.
Magnetic
properties
Non-magnetic in annealed condition.
Slight magnetism is produced by cold-working operations.
Corrosion
resistance environment behaviour
Nitric acid Good
Phosphoric acid Average
Sulphuric acid Average
Acetic acid Average
Sodium carbonate Average
NaCl (Saline mist) Average
Humidity Good
Sea water Restricted use
UGIMA
®
4305 HM has excellent ability to withstand corrosion in many environments. Its corrosion resistance
is typical of an austenitic steel and is similar to that of the 4305 / 303 in every respect.
 The use of UGIMA
®
4305 HM is compatible with all the fluids, lubricants, oils and greases used in the
machining industry.
 However, UGIMA
®
4305 HM is not recommended for use in marine environments and highly
oxidising chemical environments.
 In addition, as with all resulphurised steels, special care must be taken when using UGIMA
®
4305
HM in acid or chloride environments that are liable to pitting and crevice corrosion, it should not be used
where components are shaped in such a way as to have areas where corrosive products might collect and
corrode.
 Optimum corrosion resistance is obtained where a surface is free from all traces of machining oil or
foreign particles (of iron for example).
UGIMA
®
4305 HM is pickled in the same way as 304 grade steel.
Decontamination of steels with a high sulphur content is not recommended owing to the complexity and cost
of this operation; however, if it is necessary, the recommended decontamination / passivation process is as
follows:
1 volume 52% nitric acid (36° Baumé)
1 volume water
ambient temperature
short duration
wash carefully when the process is completed
 The corrosion resistance of a stainless steel depends on many factors related to the composition of
the corrosive atmosphere (chloride concentration, presence or absence of oxidising agents, temperature, pH,
agitation or no agitation, and so on), as well as to the preparation of the material (surfaces free from metal
particles, surface finish, such as hardening, polishing, and so on). Precautionary measures should be taken
for certain tests such as the saline mist test (French standard NFX 41002): for example marking labels (that
might cause corrosion run-outs and reduce the test resistance time) should not be used on the sample.

3. UGIMA®
4305HM
Chemical Analysis
C Si Mn Ni Cr Cu Mo Nb P S
≤0.07 ≤0.75 1,5-2 8.2 – 9.5 17.0 - 18.0 ≤0.75 ≤0,5  5xC - < 0.45.  0.040 0.25-0.35
07-09-2011 – REV05
Avenue Paul Girod
73403 UGINE Cedex - France
www.ugitech.com
3
Although UGITECH takes special care to verify the exactitude of the information printed. here, it cannot guarantee that this information is exact, reliable complete and reproducible as such by its customers.
UGITECH refuses all responsibility for the data indicate above and invites you to contact its Technical Assistance Department for a specific study of your needs.
Machinability The performance of UGIMA
®
4305 HM in machining is exceptionally good as a result of the
optimisation of the inclusion population. This is true for very high speeds and severe cutting
conditions, as a result of the UGIMA
®
process, but also for low speeds and less severe cutting
conditions, because of the new improvements achieved through this latest development. UGIMA
®
4305 HM is therefore particularly appropriate for screw machining, as its improved machinability is
effective through an extensive range of cutting conditions and machining operations. Its
performance is based on extremely good chip breakability, extended tool life and excellent surface
finish.
If you would like to use the grade to best advantage for your components and working
environment, contact our Technical Service.
Welding Like all stainless steels with a high sulphur content, UGIMA
®
4305 HM is very difficult to weld, due
to the almost inevitable phenomenon of thermal weld cracking. This is particularly true in the case
of welding without the use of filler material.
If a weld is required, it is recommended that ER312 welding wire be used as the filler metal to
minimise thermal cracking problems. Heat treatment must not be performed after welding with
ER312 wire.
Heat treatment The annealing treatment that gives UGIMA
®
4305 HM its lowest properties includes heating to
1000 - 1100°C, followed by rapid air or water cooling.
In this case, the properties obtained will be:
Rm 575 - 650 Mpa
Rp 0.2 > 250/350 Mpa
A% > 65/50
Forging
The forging of UGIMA
®
4305 HM is not recommended. However, if this operation is indispensable,
the material should be heated to 1175 - 1205° C, and the work should be finished at a
temperature higher than 955°C
Products
available
Produit Forme Finition Tolérance
Bars Rolled 13
Bars Descaled 13
Turned bars 6 to 11
Ground bars 6 to 11
Other presentations: please consult us