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Патент USA US2110891

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2,110,891
UNITED STATES" PATENT OFFICE
Pateii'ted Niar. 15, 1238
CORROSION-RESISTANT AND COLD WORK
~ABLE MOLYBDENUM STEEL
Heinrich Reitz, Bitterfeld, and Erich Hengler and
‘Alfred Biittinghaus, Wetzlar, Germany
vNo Drawing. Application May 'I, 1936,‘ Serial’ _
-
No. 78,316.
In Germany May 7, 1935'
'5 Claims. (Cl. 75-126)
aqueous solutions of chlorine, hypochlorous acid
ever, other elements may be used in lieu of tita
nium with satisfactory results. Thus, such car
bide-forming elements as vanadium, tantalum,
and their salts.
uranium, niobium, cerium, boron, zirconium and
The present invention relates to steels capable
of resisting attack by corrosive media including
5
_
.
One of the chief problems with which the pres
ent day metallurgists are faced is a meeting of
the demand by the chemical arts for steels which
will withstand corrosive chemicals and still be
capable of being mechanically worked.
This
1) problem is particularly onerous as regards those
industries‘which employ solutions of chlorine
containing substances, since, as is known, ferrous
metals are very susceptible to attack by these
tungsten may be used as substitutes for titanium.
As previously noted, we have found it prefer
able in making up our alloys to maintain a low
content of carbon, that is less than about .5%.
The chromium content of the alloys ‘should
range between about 12 and 30%, preferably
between aboutZ20 and 30%. The molybdenum
content may be as high as 5% and should‘ ex
ceed about 1.5%. . The titanium or other carbide
substances. In fact, screens and the like used forming-element should be present in an amount.
' in ?ltering apparatus ingthe manufacture of hy ' of from about .5 to 3.5%. The addition of small 15
pochlorites, when made of so-called stainless amounts of manganese and silicon are also to be
steel, are so vigorously attacked that their utility recommended. Thus the steel preferably con
is completely impaired after only short periods
of service.
»
-
_
Chromium is one 'of the alloying ‘elements
which is most commonly employed in steels de
signed for use in chemical apparatus. This ele
ment has the function, among others, of improv
ing the corrosion resistance of the steel. Molyb
denum has recently come into rather extended
use, usually with chromium as an ,agent‘for in-,
creasing
or imparting
corrosion- resistance.
Neither this element nor chromium, nor both to
gether, however, is capable of giving steels this
property to» an extent su?icient to withstand the
attack of different chemicals especially solutions
of chlorine-containing substances. Moreover,
molybdenum, when used in large amounts, has a
marked tendency to render ste'els brittle thereby
impairing their capability of being mechanically
worked in the cold, that is cold rolled,.cold drawn
and cold hammered. Any increase in corrosion
resistance resulting from the use of large pro
I portions of molybdenum is, therefore, offset by a
40 decrease in the mechanical cold workability of
the steels.
‘
The purpose of this invention is to provide
a chromium-molybdenum low-carbon steel which
tains from about .3 to about .6% of manganese
and less than .5% of silicon. The balance of the 1
steel is iron with the usual negligible quantities of
impurities generally present in stainless steels.
These steels), especially when prepared with
titanium, not only are remarkably resistant to
corrosion by chlorine-containing solutions but
also possess the property of being
cold hammered and cold drawn. An
their resistance to corrosion may
from the fact that said steels are
cold rolled,
estimate of
be gleaned
capable of
withstanding attack by the very corrosive calcium
hypochlorite solutions even‘ at a temperature of 30
110° C. Said steels may, therefore, be employed
for all purposes where steelsof these properties
are required. Thus they are admirably ?tted for
the manufacture of wire screens for ?ltering
chlorine- and hypochloride-containing- mashes vi
and lyes and perforated supporting discs for such
?lters as well as armatures, armature accessories,
pumps, containers, valves, slide bars and the
like which during use contact chlorine-contain
ing solutions.
'
40
-
The following illustrates typical alloys'within
the scope of our invention:'
-
_
will be resistant to attack by aqueous solutions
aa 5 of chlorine, :hypochlorous acid, their salts and
the like, and at the same time willpossess the
1. Carbon
Manganese
desired mechanical properties of being ‘ cold
_
I
g
__
Per
cent
:less than‘______ _-_l
=_ ______________ __
0,50 ,
0,30- 0,60 45
Silicon
=less than _______ __
0,50
Chromium
=_____v _____ _~______ 12,5 -30,0
'
rolled, cold drawn, cold hammered and the like to
Molybdenum =____- ___________ __
1,50- 5,00
a high degree.
Titanium
0,50-
"
= _____ __- _______ __ . _
3,50
'~ We have discovered that if there is included _Balance iron and negligible quantities of usual 50
'
in low' carbon-chromium-molybdenum steels an impurities.
alloying ingredient capable of forming carbides,
in such quantities ‘that after a ?xing of the free
carbon as carbide there remains su?'lcient of the
ingredients to form mixed crystals with the other
alloying ingredients, steels, of a resistance to
chlorine-containing solutions which could not
be'foreseen are obtained. The alloying ingredi
ent that we‘ have found most siutable for use and
which we therefore prefer, is titanium. How
'
2. Carbon
Manganese
Per cent
:‘less than _______ __
,_—_ _______________ __
0,10
0,40- 0,60
Silicon
=less than _______ __
0,50
Chromium
Molybdenum
= _______________ __ 16,0 -18,0
= ______ -i _____ __,_-_
1,80- 2,40
Titanium
=___.__-_ _________ __
0,80- 1,20
Balance iron and negligible quantities of usual
impurities.
-
'
60
.2
2,110,891
Per cent
F _______________ __ '0,20- 0,30
= _______________ __
0,40- 0,60
bium, cerium, boron, zirconium or tungsten. .
However, when such metals are used in lieu of
titanium, it is preferable to maintain the propor
Silicon
=less than. ______ __
0,50
tions of elements of Example 5.
Chromium _
=__-_ ____ _'_ ______ __ 23,0 -25,0
'3. Carbon
Manganese
h
Molybdenum = _______________ __
2,80- 3,30
Titanium'
1,80- 2,40
= _______________ __
Balance iron and negligible quantities of usual
impurities.
10
Silicon
15
Per cent
4. Carbon
Manganese
'
= _______________ __
= _______________ .._
0,18- 0,22
0,40- 0,60
=less than _______ __
0,50
.
Chromium
= _______________ __ 27,0 —29,0
Molybdenum. = _______________ __
1,60- 2,00
Titanium
'
= _______________ __
1,20- 1,60
Balance iron and negligible quantities or usual
impurities.
-
.
5'. Carbon
20
Per cent
=less than _______ .._
0,50
Manganese
= ________ -'_ _____ __
0,40- 0,60
Silicon
=less than _______ __
0,50 .
Chromium
= ______ ..:_______ _.. 20,0 -30,0.
Molybdenum =_.______________ __
1,80- 4,00
Titanium
0,50- 3,50
= _______________ __
25 Balance iron and negligible quantities of usual
impurities.
4
-
‘Titanium has heretofore. been used in steels
but primarily for the purpose of effecting de
oxidation thereof.
This use is in no way com
parable to‘our use of titanium. On the con
trary, the presence of titanium in our steels‘
serves the purposes of augmenting the corrosion 10
resistance of the steel imparted by the m’olyb
denum and 01! preventing the molybdenum from
destroying the desired mechanical properties of
the steel such as its cold rollability, cold ductility
and cold malleability. Thus, the steels have a 15
much greater resistance to corrosion than could
be imparted to them by molybdenum alone, and
at the same time are capable of being mechani
cally worked in the cold despite the presence of
vsubstantial quantities or molybdenum.
The two fold function of the titanium in our
steels is developed in the accompanying tables
which compare the corrosion resistance and cold
malleability oi’ chromium-molybdenum steels 25
with chromium-molybdenum-titanium steels. .
\
(1)
30
30
Low 0! weight in
grams/sq. meter of
surface in 1 hour
Depth
inmm.
ina
35
c
Mn
51
Cr
Mo 11% Acetic
‘:32
5
'
‘5185]
tem- ,
ra-
. ‘genre
107
H1864
m. “115k.
3:8. 0
-H%
tcmWe‘
tem-
mm
‘mm’
90’ C.
turo
90°C
40
0,10
040-0,00
0,07
'0,40-0,00 0,30-1
0,08
030-1
14,92’
0:40-0,60 0130-1
2,0 .... --
15,97
'
2,0 0,45
17,00-
2,31
2,0 0,93
0,62
m
BNO; Mm to
Erich
sen '
00 0.
105
2,3
11205
0,001
1,152
0,000
40
,3
10,85
i0,40
45
(2)
50"
Loss 0! weight in
grams/sq. meter of
surface in 1 hour
I
-
50
llgepth
NaOCi ,3?
‘oil!
aimngg‘ mm.in
SOlllUOlJ
0
Mn
Si
'
.
Cr
-
207
‘
n8
Mo T195 107 13,86‘ gm5__
8
4 +4%
83
ZPC.
HNOI
chlorine
Del‘ It
tag:
-
80mm
I Erlclb
at.
and400
“n
20°C
grams oi
.
0801:
60
at
20°C
0,27
65
o,40-0,co o,ao-l
0,07 _0,,40-0,60 0,30-1
24,83 2,0
26,70
____ "10,5 ' 0,021
2,30 .... __ 10,0
,
'
aiming
X]
6,5’
sliligng
7,1
_
mg.
0,!)
0,40-0,60 0,30-1
26,28‘ 1,88 1,39 0,00 0,0058 lfgckat-
7,5
0,08
0,40-0,60 0,30-1
29,15 1,71 1,29 0,00 0,0000 lie kat-
8,2
0,27
0,40-0,60 0,30-1
'
,
26,28 4,00
’
ac
4,5
'
.
N01;
co
'
70
.
Fitting.
’
work
able.
‘The titanium in any of these alloys .may be
75 replaced by vanadium, tantalum, uranium, nio-
Thefasteris'ks in the above tables indicate that
the results were not ascertained with particular
2,110,891‘
ity since it was apparent from observation that
the test pieces, had'su?ered a very material de
crease in weight, a fact which was to be expected
at the outset.
-
'
impurities.
.
resisting alloys consisting of
Per cent
154 ‘of “Enzyklopaedie tier technischen ‘
Chemie” by Ullmann, volume 4, 2nd edltio .
.
.,
1. Cold ductile and cold malleable corrosion
10
' resisting alloys for use in the manufacture of
articles which require resistance to attack by
aqueous solutions ,of chlorine, calcium hypochlo
rite and their salts, containing less than .5% of
15 carbon, from about .3 to about .6% of manganese,
less than about .5% of silicon, from about 12 to
about 30% of chromium, from about 1.5 to about
_5% of molybdenum, and from. about .5 to about
3.5% of a carbide-forming element selected from
20
the class consisting of’ titanium and vanadium
in an amount of about 6 to 12 times the amount
of carbon present, the balance being. iron with
a
the usual impurities,
2. The alloy as de?ned in claim 1, wherein the
'
carbide-forming element is titanium.
3. Cold-ductile and cold malleable corrosion
resisting alloys consisting of
.
30
Per cent
Carbon
=less than _______ ..
0,10
Manganese
'_—-__-_- ___________ __
0,40- 0,60
Silicon
=less than ____ __.___
0,50
Chromium
= _____ _-______.,.-_.-_ 16,0 -18,0
Molybdenum- =' _______________ .._
Titanium
1,80- 2,40
>=..___---_-_-..-..,.-, 0,80- 1,20
,
4. Cold ductile and cold malleable corrosion
ferred to in the tables attention is directed to
What we claim is:
3
Balance iron and ‘negligible quantities of‘ usua
For a full discussion of the Erichsen test re
page
-
Carbon
= _______________ .._
0,20- 0,30
Manganese
=-'. _____________ __
0,40- 0,60
Silicon ‘
==less than _______ __
0,50
Chromium
=' _______________ __ 23,0 -25,0
Molybdenum = _______________ __
Titanium
~= _______________ __
10
2,80- 3,30
1,80- 2,40
Balance iron and negligible quantities of usual
impurities.
5. Cold ductile and .cold malleable corrosion-3
15
resisting alloys consisting of ‘
.
Per cent
Carbon
= ________________ ._ .
0,18- 0,22
Manganese
= ______________ --_.
0,40; 0,60
, Silicon
Chromium
, '=less than _______ __
20
0,50
I = __________ __-____- 27,0 -29,0
Molybdenum = _______________ -._
1,60- 2,00
Titanium -
1,20- 1,60
'=' _________ __- .... __
25'
Balance iron and negligible quantities of usual
’ impurities.
ERICH HENGIER.‘ »
HEINRICH
‘ .
~ALFRED-BU'ITINGHAUS.
30
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