MXPA00012832A - Cemented carbide for oil and gas applications - Google Patents

Abstract

The present invention relates to a cemented carbide with excellent properties for oil and gas applications regarding resistance to the combined erosion and corrosion synergistic effects at temperatures between -50 and 300°C, preferably 0-100°C. The cemented carbide contains, in wt.%, 2. 5-4.5 Co+Ni with a weight ratio Co/Ni of about 3, 0.25-0.6 Cr and 0.1 Mo wherein essentially all of the WC grains have a size<1&mgr;m and wherein the total carbon content is in the interval of 6.13 - (0.061±0.008) x binder phase (Co+Ni) content (wt.%).

Description

z CEMENTED CARBIDE FOR PETROLEUM AND GAS APPLICATIONS The present invention relates to a grade of cemented carbide with special properties for uses in oil and gas. Moreover, the invention relates to the application of a corrosion-erosion resistant grade for regulating valves to control the flow of multimedia fluids (gas, liquid and sand particles). Cemented carbide for applications that require corrosion resistance such as sealing rings, bearings, bushings, hot rollers, etc., generally have a binder phase consisting of Co, Ni, Cr and Mo wherein Cr and / or Mo they act as corrosion inhibiting additives. An example of a cemented carbide of this type with an average grain size WC is described in EP 28 620. EP 568 584 describes the use of a corrosion-resistant cemented carbide with a smaller grain size than a miera with excellent properties, particularly for tools in the lumber industry. A critical component in submarine oil / gas production systems are the components of the compensation regulator, whose primary function is to control the pressure and flow of well products. Under severe conditions of multiple flow media, these components even when fitted with cemented carbide compensators can suffer from extreme loss of mass due to exposure to solid particle erosion, acid corrosion, erosion-corrosion synergy and cavitation mechanisms. The opportunity to maintain or replace such equipment in the field, especially in offshore locations in deep water is limited by weather conditions. It is therefore essential that reliable and predictable products form part of the submarine system. The composition of the cemented carbide grades used in the present for service-resistant conditions in this environment, generally consists of tungsten carbide (WC) as the hard component and cobalt (Co) or nickel (Ni) as the binder for cementing together the WC crystals. To achieve the demands of firmness and hardness, the amount of binder and / or WC-sized grains are varied and cobalt is generally accepted as the optimum binder component. Where corrosion is the predominant factor, then the binder material is usually nickel or a nickel + chromium (Ni + Cr) composition.

Analogous to stainless steels Cr and Ni alloys have improved passivity by reducing the critical currents involved in corrosion, however (Cr + Ni) are not as resistant to halides (seawater) or inorganic acids. For these conditions, the addition of molybdenum provides improved resistance to corrosion as well as improving the strength of the Ni binder. Recent experimental works, including evaluations of field tests, have proven that in cases of high erosion conditions under a corrosive medium, then the mechanisms of mass loss are a combination of each condition but still more of synergy. The present invention relates to the use of cemented carbides with excellent properties with respect to resistance to the combined synergistic effects of erosion and corrosion at temperatures between -50 and 300 ° C, preferably 0-100 ° C. Resistance to particle erosion under a corrosive environment has been achieved by using a sintered specifically optimized multi-alloy binder with a WC size below one miera, i.e., essentially all WC beads have a size < lm The cemented carbide according to the invention has the composition, in percent by weight. 2.5-4.5 Co + Ni with a Co / Ni weight ratio of approximately 3, 0.25-0.6 Cr and approximately 0.1 Mo. In a preferred embodiment, the cemented carbide has the composition 3.3% Co, 1.1% Ni, 0.52% Cr, 0.1% Mo with the WC balance with an average grain size of 0.8 Dm. In another preferred representation, the composition is 1.9% Co, 0.7% Ni, 0.3% Cr, 0.1% Mo with a WC balance of 0.8 Cm. The carbon content in the sintered cemented carbide must be kept within a narrow band to retain a high resistance to corrosion and wear as well as hardness. The total carbon content should be within the range of 6.13- (0.06110.008) per content (in weight percentage) binder phase (Co + Ni), preferably 6.13- (0.061 ± 0.005). The firmness of the cemented carbide according to the invention should be >; 1875, preferably > 1900 HV30 and the TRS as determined according to the IS03327 type B test on test pieces must be > 2100, preferably > 2200 N / mm2. The cemented carbide used in this invention is manufactured by conventional metallurgical powder grinding, pressing, forming and sintering methods. The cemented carbide according to the invention is particularly applicable to the components of the compensation regulator used in the oil and gas industry where the components are subject to high pressures of multiple media fluids where there is a corrosive environment including water of the sea Example 1 A cemented carbide according to the invention had the composition 3.3% Co, 1.1% Ni, 0.6% Cr C2, 0. 1% Mo with a WC balance, a firmness of 1900 HV30 and transverse breaking strength (TRS) of 2350 N / mm2 with average WC grain size of 0.6 Dm. It was tested in comparison to a commercially available cemented carbide grade 1 made with 6% Co and the others with 6% Ni both with the WC balance (0.8 Cm) under the following simulated test conditions: Synthetic seawater - Sand 18 m / s - C02 at 1 Bar - Temperature 54 ° C.

The following results were obtained. Material loss of units: mm / year Degree Corrosion Erosion Total Synergy WC 6% Co 0.02 0.09 0.35 0.46 WC 6% Ni 0.015 0.265 0.17 0.45 Invention 0.015 0.06 0.025 0.10 Example 2 The cemented carbides were prepared in accordance ^^ 10 with the invention with the composition of 3.3% Co, 1.1% of Ni, 0.6% Cr3C2, 0.1% Mo with a WC balance of 0.8 Dm, referred to as grade 1 and grade 2 consisting of a Similar alloy composition but with reduced proportions of 1.9% Co, 0.7% Ni, 0.35% Cr3C2, 0.1% Mo with a WC balance. These materials had values of firmness of 1900 HV30 and 1910 HV30 and breaking strength ? cross section (TRS) of 2350 N / min2 and 2350 N / mrn2 respectively, each with an average WC size of 0.6 Dm. They were tested in comparison with cemented carbide grades commercially available under the following simulated test conditions of seawater and sand. The flow rate: 90 m / s and collision angles of 30 ° and 90 °.

The following results were obtained. Material loss of units: mm3 / k of sand.

Degree Erosion Erosion 30 ° 90 ° WC 6% Co 1.6 1.4 WC 6% Ni 2.1 1.6 1 (invention) 0.5 0.3 A cemented carbide according to the invention with the composition 3.3% Co, 1.1% Ni, 0.6% Cr3C2, 0.1% Mo, with a WC balance and a firmness of 1900 HV30 and a transverse breaking force (TRS) ) of 2350 N / mm2 with an average WC size of 0.6 Cm was tested in comparison with grades of commercially available cemented carbide. The test conditions of air and sand at 200 m / s: Flow rate: 200 m / s of air and collision angles of 30 ° and 90 °. The following results were obtained. Material loss of units: mm3 / k of sand.

Degree Erosion Erosion 30 ° 90 ° WC 6% Co 2.5 4.0 WC 6% Ni 2.6 5.6 Invention 0.8 1.4 Cemented carbide according to the invention shows a significant reduction in wear measured in volume loss.

Claims (6)

1. - Carbide cemented with excellent properties for uses in oil and gas with respect to the resistance to the combined synergistic effects of erosion and corrosion at temperatures between -50 and 300 ° C, preferably 0-100 ° C, characterized in that it contains, as a percentage of weight, 2.5-4.5 Co + Ni with a Co / Ni weight ratio of approximately 3, 0.25-0.6 Cr and 0.1 Mo where essentially all the WC grade grains have a size < 1 Dm and where the total carbon content is within the range of 6.13- (0.06110.008) per content (in percentage by weight) binder phase (Co + Ni).

2. Cemented carbide according to the previous claim characterized by the composition 3.3% Co, 1.1% Ni, 0.52% CR, 0.1 Mo with WC balance.

3. Carburized cemented according to claim 1, characterized by the composition 1.9% Co, 0.7% Ni, 0.3% CR, 0.1 Mo with WC balance.

4. Cemented carbide according to any of the preceding claims characterized by a carbon content within the range of 6.13- (0.061 + 0.005) per content (in percent by weight) binder phase (Co + Ni).

5. Use of a cemented carbide according to claims 1 to 4 for uses in oil and gas especially for components, whose primary function is to control the pressure and flow of well products. CEMENTED CARBIDE FOR PETROLEUM AND GAS APPLICATIONS SUMMARY The present invention relates to a cemented carbide with excellent properties for use in petroleum and gas with respect to its resistance to the combined smergetic effects of erosion and corrosion at temperatures between -5G and 30Q ° C, preferably from 0 to 100 ° C. . Cemented carbide contains, in weight percentage, 2.5-4.5 Co + Ni with a Co / Ni weight ratio of approximately 3, 0.25-0.6 Cr and 0.1 Mo where essentially all WC grains have a size of < μm and where the total carbon content is in the range of 6.13 - (0. OdljU .008) by content (in weight percentage) of binder phase (Co + Ni).