DE1558549A1 - Steel alloy and pipes made from it - Google Patents

Description

The invention relates to a low-carbon steel " alloy with great tensile strength, which can be used in many ways and is particularly suitable for the production of welded Steel pipes are suitable «

In particular, the invention relates to a steel alloy having a high tensile strength. .

Is are already steel alloys with 'X-60 large train' strength known for the manufacture of steel tubes; with these Alloys, however, is Golumbium and / or Fanadiuia as an addition * Borrowed Component to Manganese Required «According to the provision According to 7021 iPI (1966), these alloys should be less than 0

Sulphurous matter, less than 1.35% Ivlangan, less than 0.04 $ phosphorus, less than O _t Q5Q # sulfur, above 0.01 # Cb and above 0.02 ^ V. It is also stated that the alloy should contain Cb and / or V »

Since these steel alloys are mainly produced according to the calmed process * these steels do not have the fine-grained structure of an alloy with a high carbon content and must therefore be rolled using a special low-temperature rolling process under the ideal efficiency "Further, the SChv / eißbarkeit such alloys as a result of yerhältnisroäßif ^(is; gro3en carbon ens toffgehalts low * Since it is read in a semi-killed steel that this steel is not uniform *

The invention scnafft a steel alloy of the general type described above, wherein the above beschrie "surrounded disadvantages of beka _n nth Stahllegierimgen of this type do not occur *

009818 / 06SS bathroom «*» · * -

In particular, the invention provides a low-carbon steel alloy with high tensile strength in which no addition of relatively expensive columbium and / or Vanadium is required

The invention also provides a steel alloy *

of

in the case of / instead of expensive columbium and / or vanadium less expensive substances are used and the desired alloy properties are greatly improved at the same time are.

The invention ... also creates a steel alloy, which is very £ ut for many uses * in particular but suitable for the production of welded steel tubes

The. Iminding creates steel objects with large Tensile strength and very good quality made from steel plates are produced, which by rolling a nieiriggekohlten Steel alloy of the above general type were obtained »

The low carbon steel alloy according to the invention with great tensile strength includes liangan, Kupier and Chroa;

BATH ORIGINAL 009816/0655

the relatively cheap copper and chromium are used instead of the much more expensive columbium and vanadium, although far better results are achieved. Welding experience with concealed light * · arcs, welded v. ^r _# ird In this way, steel pipes can be produced large tensile strength with a 60-X, whose tensile strength is about 5480 kg / cm (78 OOOpsi). The chemical composition of this low carbon steel alloy according to the invention is less than $ 0.23 carbon, less than $ 0.50 silicon, $ 1.00-1.50 manganese, less than $ 0.040 phosphorus, less than $ 0.040 sulfur, less than $ 0.30 copper, less than $ 0.50 chromium, $ 0.010 to $ 0.050 aluminum and otherwise of iron and impurities, the amount and type of which do not impair the desired properties of the alloy «

In this way, the strength is dc-r according to the invention Low-grade steel alloy of the above-mentioned low-cost composition, while the cheap copper and chromium instead of the much more expensive columbium and vanadium

009816/0655

is used »In addition, the cutting toughness of the alloy is improved and di.e the desired properties are stabilized by producing the alloy according to the aluminum-calmed process « represents * Compared to the conventional, columbium and * Vanadium containing alloys of the above type becomes the carbon content of the alloy of the present invention greatly reduced, in order to improve welding ability » Furthermore, a fine-grain structure is achieved in the alloy according to the invention, whereby a reduction in the effect. degree of the rolling process is avoided * that of the conventional Alloys as a result of the required temperature control due to the critical amount of the various Elements of conventional alloys is inevitable »

The carbon content of the alloy according to the invention is less than $ 0.23; the minimum carbon amount is 0.10 ^ <in terms of the value of the carbon equivalent

BATH ORlGMAL 0 0 9816/0655

Those in the alloy: jum to achieve the required iii material strength shall be the amount of silicon present a maximum of $ 0.50 and a minimum of $ 0.20 «Otherwise the a required strength not achieved »

With conventional steel alloys, the sulfur and the amount of phosphorus is preferably kept fairly low; however, it has been found that no adverse effects occur if the amount of these two elements is 0.040 does not exceed »

If the copper level exceeds $ 0.30, join Roll through a brittleness, heat up; if the Chromgenalt exceeds $ 0.50 »causes this due to the The value of the carbon equivalent generally increases the hardness of the material, causing difficulties in welding appear. The alloy according to the invention therefore contains less than $ 0.30 copper and less than $ 0.50 chromium,

Since the grain formation due to the presence of aluminum is not noticeable at a content of up to 0.10 $ and, on the other hand, cracks occur in the steel block at an aluminum content of over 0 _t 080 # ^ the aluminum is gerialt in the alloy according to the invention between 0.010 $ and U .80 $ held *

009816/0655 ~ ⁷ ~

BATH

If the manganese content is less than 1.0%, the required strength is not obtained, whereas if the manganese content is over 1.50, the weldability of the alloy is impaired, as is the case if the chromium content is too high. The manganese content is therefore impaired held between £ 1.00 and £ 1.50, preferably between $ 1.00 and $ 1.35

Description of a preferred embodiment according to FIG

invention

The invention will now be carried out in a preferred embodiment explained in more detail.

According to the invention, a steel pipe with a high tensile strength is produced by the methods described above, by shaping the steel according to the method described above. Aluminum Derunigte procedure and. hn gutm ζλ e_: ier stand plate rolled out * The low-carbon stabilizer according to the invention contained 0.15-0.20 pounds of carbon, δ, 20-0,: · 0 # silicon, 1.00-1.35? Manganese, 0.10-0.20 # copper, and 0.10-0.40 # chromium.

The strength, cutting toughness, weldability * unevenness of strength, corrosion resistance and

· »□ · ■«

009816/0655

BATH ORIGINAL

Similar properties of a tube made from this alloy by the hidden arc method were compared with the corresponding properties of tubes made from known steel alloys; for comparison, an alloy with a content of 0 _t 16% carbon, 1.00 ~ 1.40 # manganese and 0.005 ~ 0.04 # columbium was used; the other alloys with which the structure: According to the invention was compared contained 0.19-0.26 £ carbon * 1.00-1.305 * manganese and 0.01-0.09 # vanadium; all of these known steel alloys did not contain silicon.

The comparison results ν ar en as follows:

1) Strength Retention: In terms of strength retention (life), the tube made with the alloy of the invention and the tubes made with the conventional alloys generally had the same tensile strength of over 4,220 kg / cm ² (60,000 psi ) on*

009816/0655

ORIGlNAL BATHROOM

2) Cutting toughnessί

The tubes made with the conventional alloys had a $ 50 shear rupture temperature of "34" +4 ⁰ C ("30 w +40 ⁰ F) "while the steel alloy according to the invention had an improved bO # se" rupture temperature of "-" 62 to - # 51 C ("80 to" * 60 ° F) had *

3) weldability!

The steel alloy according to the invention exhibited a weldability on ^ their carbon " equivalent (USA) with alloys with a content of 0 ^ 33 to 0 * 49 $ columbium or 0 * 35 until 0 * $ 45 vanadium was comparable * to the Alloy according to the invention can therefore achieve a weldability that was previously only possible can be achieved with alloys with a relatively large content of these expensive substances could*

"10" * 009816/0655

- ίο *

4) Rolling efficiency:

As a result of the conventional alloys required Temperature control results in a reduction in the thermal efficiency of these alloys on the order of $ 15 on »where absolute i: a reduction in the rolling efficiency occurs when the alloy according to the invention is rolled «

5) Unevenness of the festi

In the case of co-ordinate »'according to the calmed down procedure In prepared steel alloys, the unevenness of strength was β ~ 7 kg / mm; on the other hand, the non-uniformity of the strength of the invention after the calmed Process of produced steel alloy 4 «5 kg /

2
mm «

6) Corrosion resistance:

When the alloys according to the invention were compared with the conventional alloys a considerable improvement in corrosion

009816/0655 ~ 11 «

BAD NAL

on strength »The corrosion of the steel alloy according to the invention was less than 10 5 ^ which is a great improvement over the corrosion resistance of known alloys represents «

According to the invention, one can therefore use a low obtained carbon steel alloy with great tensile strength * which is particularly suitable for the manufacture of steel pipes » by replacing the still-carbonized steels containing expensive columbium or vanadium with "low-carbon steels." with a content of copper i. i cnrom used 'by' use of the low carbon steel in the alloy according to the invention, the weldability becomes compared to known ones Alloys öeträch-borrowed improved »Furthermore the grain formation is effected by one in the manufacture the Sai alloy according to the invention calmed the aluminum Apply the method instead of using it during the rolling process as in the known embodiments; through this not only does the efficiency of the rolling process improve sert $ but also the unevenness of strength reduced »With the alloy according to the invention

009816/06 55 _BÄD

therefore objects, such as steel pipes, with great tensile strength and very good quality manufacturing using an alloy and clay process that compares to conventional ones Alloys and processes are simple and cheap »

The embodiment described above relates primarily to the division of API ~ · 60 high pull « solid steel pipes; However, the alloy according to the invention can also be used to produce steel plates with large Yield Strength * Steel mold blocks of various configurations, as well as other steel objects and especially for making steel for use at low temperature are applied

~ 13 ~ 009816/0655 _D

Claims (1)

Patent claims: 1β steel alloy with high tensile strength, containing less than 0.23 $ carbon, less than 0.50 $ _t silicon, 1.00 to 1 _f 50 $ siangan, less than O ₉ OW phosphorus, less than 0.040 $ Sulfur, less than 0.30 $ Καιροί er, less than 0.50 $ chromium, 0.010 to 0.080 $ aluminum and otherwise iron and impurities which do not impair the desired properties of the steel alloy * 2ο alloy according to claim 1, characterized in ** net ,, that the steel alloy consists of a killed steel «· stands" 3 * Alloy according to claim 2, characterized in that * net that the alloy consists of an aluminum killed steel * 009816/0655 «14 - 4. Alloy according to claim 1, characterized in, that they are not less than 0.10 # carbon, preferably 0.20 to 0.50 $ silicon, and preferably 1.00 to Manganese contains * 5 * steel alloy containing 0 ₇ 15 to 0.20 # carbon, 0.20 to 0, ί} 0 # silicon, 1.0 to 1.355 * manganese, 0 _t 10 to 0.20 # copper and 0.10 to 0 , 40 ^ chrome, 6 _# Welded steel pipe with a wall made of a steel alloy with high tensile strength, containing less than 0.23 # Konlenstoff. less than 0.50 # silicon * 1.00 to 1.50 # manganese, less than 0.040 # phosphorus, less than 0.040 # sulfur, less than 0.30 # copper, less than 0.505 ^ chromium * 0.010 ^ to 0.080 ^ aluminum and otherwise iron and impurities which do not affect the desired properties of the pipe. 009816/0655